Airborne electromagnetic (AEM), magnetic, and radiometric data were acquired May 25 through August 7, 2021 along 10,706 line-kilometers (line-km) over the Mississippi Alluvial Plain (MAP). Data were acquired by Xcalibur Multiphysics with three different helicopter-borne sensors: the Xcalibur Multiphysics Resolve frequency-domain AEM instrument that is used to map subsurface geologic structure at depths up to 100 meters, depending on the subsurface resistivity; a Scintrex CS-3 cesium vapor magnetometer that detects changes in deep (hundreds of meters to kilometers) geologic structure based on variations in the magnetic properties of different formations; and a Radiation Solutions RS-500 spectrometer that detects the abundance of natural radioelements potassium, uranium, and thorium in the upper 20-30 cm that is used to determine differences in soil constituents. The survey was flown at a nominal sensor flight height of 30 m above terrain. Sixteen rivers were surveyed along their center axes, covering 3,467 line-km. Ten rivers are within the surficial Mississippi River Alluvial aquifer boundary: Black River, White River, Big Sunflower River, Little Sunflower River, Ouachita River, Tensas River, Obion River, Saline River, Little Red River, and Bogue Phalia. Six rivers are within the Chicot aquifer boundary: Vermillion River, Bayou Teche, Mermentau River, Calcasieu River, Sabine River, and Bayou Lacassine. Select levee reaches were surveyed along the Mississippi and Arkansas Rivers along the riverside toe, landside toe, and 91m landward offset from the landside toe for a total of 5,896 line-km. Four grids were flown over gravel bars in the Mississippi River: Prairie Point block, Island 63 block, Crumrod block, White River block, and three short segments along the Mississippi River targeting gravel bars. Three additional grids were flown: (1) Melton site in Mississippi with 100-m spaced north-south flight lines for a total of 23 line-km, (2) optically stimulated luminescence (OSL) core study site in Arkansas with 500m east-west line spacing for a total of 268 line-km, and (3) Raccourci Lake in Louisiana with variable flight lines for a total of 100 line-km. Additional detail on flight line numbers is included in the supplemental section. Also included is a small levee dataset acquired in March 2018 near Greenville, Mississippi during the Shellmound AEM survey https://www.sciencebase.gov/catalog/item/5c9e6c42e4b0b8a7f62f5da6. This dataset does not contain magnetic and radiometric data. The survey includes four lines parallel to and over the levee for a total of 27 line-km. This data release includes the averaged and culled AEM data along all flight lines that were used to produce the final resistivity models for both surveys https://www.sciencebase.gov/catalog/item/5d76ba5ce4b0c4f70d01ff94 Digital data of the processed soundings are provided and fields are defined in the data dictionary https://www.sciencebase.gov/catalog/item/5d76bac9e4b0c4f70d01ff9d.

Airborne electromagnetic (AEM), magnetic, and radiometric data were acquired May 25 through August 7, 2021 along 10,706 line-kilometers (line-km) over the Mississippi Alluvial Plain (MAP). Data were acquired by Xcalibur Multiphysics with three different helicopter-borne sensors: the Xcalibur Multiphysics Resolve frequency-domain AEM instrument that is used to map subsurface geologic structure at depths up to 100 meters, depending on the subsurface resistivity; a Scintrex CS-3 cesium vapor magnetometer that detects changes in deep (hundreds of meters to kilometers) geologic structure based on variations in the magnetic properties of different formations; and a Radiation Solutions RS-500 spectrometer that detects the abundance of natural radioelements potassium, uranium, and thorium in the upper 20-30 cm that is used to determine differences in soil constituents. The survey was flown at a nominal sensor flight height of 30 m above terrain. Sixteen rivers were surveyed along their center axes, covering 3,467 line-km. Ten rivers are within the surficial Mississippi River Alluvial aquifer boundary: Black River, White River, Big Sunflower River, Little Sunflower River, Ouachita River, Tensas River, Obion River, Saline River, Little Red River, and Bogue Phalia. Six rivers are within the Chicot aquifer boundary: Vermillion River, Bayou Teche, Mermentau River, Calcasieu River, Sabine River, and Bayou Lacassine. Select levee reaches were surveyed along the Mississippi and Arkansas Rivers along the riverside toe, landside toe, and 91m landward offset from the landside toe for a total of 5,896 line-km. Four grids were flown over gravel bars in the Mississippi River: Prairie Point block, Island 63 block, Crumrod block, White River block, and three short segments along the Mississippi River targeting gravel bars. Three additional grids were flown: (1) Melton site in Mississippi with 100-m spaced north-south flight lines for a total of 23 line-km, (2) optically stimulated luminescence (OSL) core study site in Arkansas with 500m east-west line spacing for a total of 268 line-km, and (3) Raccourci Lake in Louisiana with variable flight lines for a total of 100 line-km. Additional detail on flight line numbers is included in the supplemental section. Also included is a small levee dataset acquired in March 2018 near Greenville, Mississippi during the Shellmound AEM survey https://www.sciencebase.gov/catalog/item/5c9e6c42e4b0b8a7f62f5da6. This dataset does not contain magnetic and radiometric data. The survey includes four lines parallel to and over the levee for a total of 27 line-km. This data release includes minimally processed (raw) AEM data as well as unprocessed and processed (diurnally corrected and draped to terrain) magnetic data, and unprocessed and processed (following International Atomic Energy Agency Technical Report procedures) radiometric data, all as supplied by Xcalibur Multiphysics https://www.sciencebase.gov/catalog/item/624bd4a6d34e21f82763663c. Data acquisition and minimal processing were conducted by Xcalibur Multiphysics and described in detail in the contractor's reports. Digital data from production flights are provided, and data fields are defined in the data dictionaries.

Airborne electromagnetic (AEM), magnetic, and radiometric data were acquired May 25 through August 7, 2021, along 10,706 line-kilometers (line-km) over the Mississippi Alluvial Plain (MAP) and the Chicot Aquifer extent in the southeastern United States. These helicopter-based surveys collected data with a frequency-domain AEM system (Xcalibur Multiphysics RESOLVE), a cesium vapor magnetometer (Scintrex CS-3), and radiometric spectrometer (Radiation Solutions RS-500) at altitude of 30 meters (m) above the land surface. These sensors imaged a series of rivers and levees throughout these two areas focusing on water resources and infrastructure assessment. This data release includes minimally processed (raw) data, as supplied by the airborne survey contractor (Xcalibur Multiphysics), for all three sensors along all flight lines. Additionally, the AEM survey files contain the fully processed data (all corrections applied and any anomalies removed, but before any modeling), and inverted resistivity models (final modeled data) along all flight lines. Data files contained in this data release include: Contractor's report- Description of data acquisition and minimal processing as conducted by Xcalibur Multiphysics (Airborne Survey Contractor). Data were collected on the following 16 rivers: Rivers within the MAP boundary: Black, White, Big Sunflower, Little Sunflower, Ouachita, Tensas, Obion, Saline, Little Red, and Bogue Phalia. Rivers within the Chicot Aquifer extent : Mermentau, Calcasieu, Sabine, Vermillion, Bayou Teche and Bayou Lacassine. Select levee reaches were surveyed along the Mississippi and Arkansas Rivers. Where possible, lines were flown along the toe of the levee both on the side adjacent to the river and on the side opposite the river. In addition, where possible, a third line was flown 91m (300 feet) offset from the toe of the levee opposite to the river. Additional processing was done on all levee lines and is described in the data dictionaries and processing step sections of the metadata included in the “Processed Data” and “Resistivity Models” child items of this data release. Seven gridded surveys were collected also: Four grids at different resolutions were collected over gravel bars within the Mississippi River 250 m Line Spacing Prairie Point Island 63 Crumrod 100 m Line Spacing White River 23 line-km at a 100 m line spacing over a property near Minter City, Mississippi (referred to as the Melton grid). 268 line-km at a 500 m spacing over a series of the drill core locations near Paragould, AR. Referred to in this release as the AR OSL grid. 100 line-km at variable spacings over Raccourci Old River, a relic oxbow near Batchelor, LA. Referred to in this release as the Raccourci grid. A dataset collected on small levees near Greenville, Mississippi, in March 2018 is also included in this data release. The survey includes four lines parallel to and over the levee for a total of 27 line-km. This dataset was collected as an evaluation of the technical approach used on the more comprehensive surveys in the MAP and Chicot Aquifer extents. This dataset contains AEM data only (magnetic and radiometric data were not collected). Additional detail on flight line numbers and citations for the various methods used in the collection and processing of the radiometric data is included in the supplemental section.

Airborne electromagnetic (AEM), magnetic, and radiometric data were acquired November 2019 to March 2020 along 24,030 line-kilometers (line-km) over the Mississippi Alluvial Plain (MAP). Data were acquired by CGG Canada Services, Ltd. with three different airborne sensors: the CGG Canada Services, Ltd. TEMPEST time-domain AEM instrument that is used to map subsurface geologic structure at depths up to 300 meters (m), depending on the subsurface resistivity; a Scintrex CS-3 cesium vapor magnetometer that detects changes in deep (hundreds of meters to kilometers) geologic structure based on variations in the magnetic properties of different formations; and a Radiation Solutions RS-500 spectrometer that detects the abundance of natural radioelements potassium, uranium, and thorium in the upper 20-30 centimeters that is used to determine differences in soil constituents. The survey was flown at a nominal sensor flight height of 120 m above terrain with 6-kilometer spaced east-west flight lines. The main survey block covers 22,250 line-km. The Mississippi River and the Arkansas River were surveyed along their center axes, covering 1,225 line-km (flight line numbers 500101 and 700201-700206 nonsuccessive), and three separate inset grids were flown: (1) Ozark basement reconnaissance lines with variable line spacing for a total of 234 line-km (flight line numbers 400801-401401 nonsuccessive), (2) Shellmound focus area in Mississippi with 250 m line spacing for a total of 485 line-km (flight line numbers 604501-608101 nonsuccessive), and (3) New Madrid Seismic Zone focus area in Missouri and Tennessee with variable line spacing for a total of 161 line-km (flight line numbers 710101-710401 nonsuccessive). 91-series lines are repeat test-lines flown periodically throughout the survey, with one repeat line established for each base station. 902- and 905-series lines are ~60 second high-altitude datasets collected pre- and post- flight, respectively, to evaluate the system out of ground-response. This data release includes inverted depth sections along all flight lines from the AEM data (https://www.sciencebase.gov/catalog/item/5f4e954682ce4c3d1233cb84). Digital data from production flights are provided in ASEG-GDF2 format, an ASCII format geophysical data standard that uses a self-describing collection of files to allow data to be automatically identified and read by a computer application. Data fields in the data file (.DAT) are defined in the associated definition file (.DFN). Please see the ReadME included in this data release for a description of how to interpret the .DFN files or visit https://www.aseg.org.au/sites/default/files/pdf/ASEG-GDF2-REV4.pdf for more information on the ASEG-GDF2 standard.

Airborne electromagnetic (AEM), magnetic, and radiometric data were acquired November 2018 to February 2019 along 16,816 line-kilometers (line-km) over the Mississippi Alluvial Plain (MAP). Data were acquired by CGG Canada Services, Ltd. with three different helicopter-borne sensors: the CGG Canada Services, Ltd. Resolve frequency-domain AEM instrument that is used to map subsurface geologic structure at depths up to 100 meters, depending on the subsurface resistivity; a Scintrex CS-3 cesium vapor magnetometer that detects changes in deep (hundreds of meters to kilometers) geologic structure based on variations in the magnetic properties of different formations; and a Radiation Solutions RS-500 spectrometer that detects the abundance of natural radioelements potassium, uranium, and thorium in the upper 20-30 cm that is used to determine differences in soil constituents. The survey was flown at a nominal sensor flight height of 30 m above terrain with 6- to 12-kilometer spaced east-west flight lines. The main survey block covers 13,641 line-km, including two north-south tie lines extending the length of the survey. Several rivers were surveyed along their center axes, covering 2,640 line-km (flight line numbers 8010000-8100001 nonsuccessive), and two separate inset grids were flown: (1) Crowley's Ridge in Arkansas with 1.5-km spaced east-west flight lines for a total of 406 line-km (flight line numbers 24025-24477 nonsuccessive) and (2) University of Memphis focus area in Tennessee with variable line spacing for a total of 129 line-km (flight line numbers 30010-30060 and 39010-39050 nonsuccessive). This data release includes minimally processed (raw) AEM data as supplied by CGG Canada Services, Ltd. (https://www.sciencebase.gov/catalog/item/5d76bafae4b0c4f70d01ffa1), the fully processed (averaged and culled) sounding data (https://www.sciencebase.gov/catalog/item/5d76bac9e4b0c4f70d01ff9d), and laterally constrained inverted resistivity depth sections along all flight lines (https://www.sciencebase.gov/catalog/item/5d76ba5ce4b0c4f70d01ff94), as well as unprocessed and processed (diurnally corrected and draped to terrain) magnetic data (https://www.sciencebase.gov/catalog/item/5d76bafae4b0c4f70d01ffa1), and unprocessed and processed (following International Atomic Energy Agency Technical Report procedures) radiometric data (https://www.sciencebase.gov/catalog/item/5d76bafae4b0c4f70d01ffa1). Data acquisition and minimal processing were conducted by CGG Canada Services, Ltd. and described in detail in the contractor's report. Digital data from production flights are provided, and data fields are defined in the data dictionary. A total field magnetic anomaly grid and a ternary radiometric image are provided as well (https://www.sciencebase.gov/catalog/item/5d76baaae4b0c4f70d01ff9a). REFERENCES International Atomic Energy Agency, 1991, Airborne Gamma Ray Spectrometer Surveying, Technical Reports Series No. 323, IAEA, Vienna, https://inis.iaea.org/collection/NCLCollectionStore/_Public/22/072/22072114.pdf. U.S. Geological Survey, The National Map, 2017, 3DEP products and services: The National Map, 3D Elevation Program Web page, accessed October 2018 at https://nationalmap.gov/3DEP/3dep_prodserv.html.

Airborne electromagnetic (AEM), magnetic, and radiometric data were acquired November 2019 to March 2020 along 24,030 line-kilometers (line-km) over the Mississippi Alluvial Plain (MAP). Data were acquired by CGG Canada Services, Ltd. with three different airborne sensors: the CGG Canada Services, Ltd. TEMPEST time-domain AEM instrument that is used to map subsurface geologic structure at depths up to 300 meters (m), depending on the subsurface resistivity; a Scintrex CS-3 cesium vapor magnetometer that detects changes in deep (hundreds of meters to kilometers) geologic structure based on variations in the magnetic properties of different formations; and a Radiation Solutions RS-500 spectrometer that detects the abundance of natural radioelements potassium, uranium, and thorium in the upper 20-30 centimeters that is used to determine differences in soil constituents. The survey was flown at a nominal sensor flight height of 120 m above terrain with 6-kilometer spaced east-west flight lines. The main survey block covers 22,250 line-km. The Mississippi River and the Arkansas River were surveyed along their center axes, covering 1,225 line-km (flight line numbers 500101 and 700201-700206 nonsuccessive), and three separate inset grids were flown: (1) Ozark basement reconnaissance lines with variable line spacing for a total of 234 line-km (flight line numbers 400801-401401 nonsuccessive), (2) Shellmound focus area in Mississippi with 250 m line spacing for a total of 485 line-km (flight line numbers 604501-608101 nonsuccessive), and (3) New Madrid Seismic Zone focus area in Missouri and Tennessee with variable line spacing for a total of 161 line-km (flight line numbers 710101-710401 nonsuccessive). 91-series lines are repeat test-lines flown periodically throughout the survey, with one repeat line established for each base station. 902- and 905-series lines are ~60 second high-altitude datasets collected pre- and post- flight, respectively, to evaluate the system out of ground-response. This data release includes minimally processed (raw) AEM data as supplied by CGG Canada Services, Ltd. (https://www.sciencebase.gov/catalog/item/5f4e951882ce4c3d1233cb7d), the fully processed (downsampled by averaging) sounding data (https://www.sciencebase.gov/catalog/item/5f4e953482ce4c3d1233cb82), and inverted resistivity depth sections along all flight lines (https://www.sciencebase.gov/catalog/item/5f4e954682ce4c3d1233cb84), as well as unprocessed and processed (following International Atomic Energy Agency Technical Report procedures) radiometric data as supplied by CGG Canada Services, Ltd. (https://www.sciencebase.gov/catalog/item/5f4e951882ce4c3d1233cb7d). Data acquisition and minimal processing was conducted by CGG Canada Services, Ltd. and described in detail in the contractor's report. Digital data from production flights are provided in ASEG-GDF2 format, an ASCII format geophysical data standard that uses a self-describing collection of files to allow data to be automatically identified and read by a computer application. Data fields in the data file (.DAT) are defined in the associated definition file (.DFN). Please see the ReadME included in this data release for a description of how to interpret the .DFN files or visit https://www.aseg.org.au/sites/default/files/pdf/ASEG-GDF2-REV4.pdf for more information on the ASEG-GDF2 standard.

Airborne electromagnetic (AEM), magnetic, and radiometric data were acquired November 2019 to March 2020 along 24,030 line-kilometers (line-km) over the Mississippi Alluvial Plain (MAP). Data were acquired by CGG Canada Services, Ltd. with three different airborne sensors: the CGG Canada Services, Ltd. TEMPEST time-domain AEM instrument that is used to map subsurface geologic structure at depths up to 300 meters (m), depending on the subsurface resistivity; a Scintrex CS-3 cesium vapor magnetometer that detects changes in deep (hundreds of meters to kilometers) geologic structure based on variations in the magnetic properties of different formations; and a Radiation Solutions RS-500 spectrometer that detects the abundance of natural radioelements potassium, uranium, and thorium in the upper 20-30 centimeters that is used to determine differences in soil constituents. The survey was flown at a nominal sensor flight height of 120 m above terrain with 6-kilometer spaced east-west flight lines. The main survey block covers 22,250 line-km. The Mississippi River and the Arkansas River were surveyed along their center axes, covering 1,225 line-km (flight line numbers 500101 and 700201-700206 nonsuccessive), and three separate inset grids were flown: (1) Ozark basement reconnaissance lines with variable line spacing for a total of 234 line-km (flight line numbers 400801-401401 nonsuccessive), (2) Shellmound focus area in Mississippi with 250 m line spacing for a total of 485 line-km (flight line numbers 604501-608101 nonsuccessive), and (3) New Madrid Seismic Zone focus area in Missouri and Tennessee with variable line spacing for a total of 161 line-km (flight line numbers 710101-710401 nonsuccessive). 91-series lines are repeat test-lines flown periodically throughout the survey, with one repeat line established for each base station. 902- and 905-series lines are ~60 second high-altitude datasets collected pre- and post- flight, respectively, to evaluate the system out of ground-response. This data release includes minimally processed (raw) AEM data, as well as unprocessed and processed (following International Atomic Energy Agency Technical Report procedures) radiometric data, all as supplied by CGG Canada Services, Ltd. (https://www.sciencebase.gov/catalog/item/5f4e951882ce4c3d1233cb7d). Data acquisition and minimal processing was conducted by CGG Canada Services, Ltd. and described in detail in the contractor's report. Digital data from production flights are provided in ASEG-GDF2 format, an ASCII format geophysical data standard that uses a self-describing collection of files to allow data to be automatically identified and read by a computer application. Data fields in the data file (.DAT) are defined in the associated definition file (.DFN). Please see the ReadME included in this data release for a description of how to interpret the .DFN files or visit https://www.aseg.org.au/sites/default/files/pdf/ASEG-GDF2-REV4.pdf for more information on the ASEG-GDF2 standard.

Airborne electromagnetic (AEM), magnetic, and radiometric data were acquired November 2018 to February 2019 along 16,816 line-kilometers (line-km) over the Mississippi Alluvial Plain (MAP). Data were acquired by CGG Canada Services, Ltd. with three different helicopter-borne sensors: the CGG Canada Services, Ltd. Resolve frequency-domain AEM instrument that is used to map subsurface geologic structure at depths up to 100 meters, depending on the subsurface resistivity; a Scintrex CS-3 cesium vapor magnetometer that detects changes in deep (hundreds of meters to kilometers) geologic structure based on variations in the magnetic properties of different formations; and a Radiation Solutions RS-500 spectrometer that detects the abundance of natural radioelements potassium, uranium, and thorium in the upper 20-30 cm that is used to determine differences in soil constituents. The survey was flown at a nominal sensor flight height of 30 m above terrain with 6- to 12-kilometer spaced east-west flight lines. The main survey block covers 13,641 line-km, including two north-south tie lines extending the length of the survey. Several rivers were surveyed along their center axes, covering 2,640 line-km (flight line numbers 8010000-8100001 nonsuccessive), and two separate inset grids were flown: (1) Crowley's Ridge in Arkansas with 1.5-km spaced east-west flights for a total of 406 line-km (flight line numbers 24025-24477 nonsuccessive) and (2) University of Memphis focus area in Tennessee with variable line spacing for a total of 129 line-km (flight line numbers 30010-30060 and 39010-39050 nonsuccessive). This data release includes minimally processed (raw) AEM data, as well as unprocessed and processed (diurnally corrected and draped to terrain) magnetic data, and unprocessed and processed (following International Atomic Energy Agency Technical Report procedures) radiometric data, all as supplied by CGG Canada Services, Ltd. (https://www.sciencebase.gov/catalog/item/5d76bafae4b0c4f70d01ffa1). Data acquisition and minimal processing was conducted by CGG Canada Services, Ltd. and described in detail in the contractor's report. Digital data from production flights are provided, and data fields are defined in the data dictionary. REFERENCES International Atomic Energy Agency, 1991, Airborne Gamma Ray Spectrometer Surveying, Technical Reports Series No. 323, IAEA, Vienna, https://inis.iaea.org/collection/NCLCollectionStore/_Public/22/072/22072114.pdf.

Airborne electromagnetic (AEM), magnetic, and radiometric data were acquired November 2019 to March 2020 along 24,030 line-kilometers (line-km) over the Mississippi Alluvial Plain (MAP). Data were acquired by CGG Canada Services, Ltd. with three different airborne sensors: the CGG Canada Services, Ltd. TEMPEST time-domain AEM instrument that is used to map subsurface geologic structure at depths up to 300 meters (m), depending on the subsurface resistivity; a Scintrex CS-3 cesium vapor magnetometer that detects changes in deep (hundreds of meters to kilometers) geologic structure based on variations in the magnetic properties of different formations; and a Radiation Solutions RS-500 spectrometer that detects the abundance of natural radioelements potassium, uranium, and thorium in the upper 20-30 centimeters that is used to determine differences in soil constituents. The survey was flown at a nominal sensor flight height of 120 m above terrain with 6-kilometer spaced east-west flight lines. The main survey block covers 22,250 line-km. The Mississippi River and the Arkansas River were surveyed along their center axes, covering 1,225 line-km (flight line numbers 500101 and 700201-700206 nonsuccessive), and three separate inset grids were flown: (1) Ozark basement reconnaissance lines with variable line spacing for a total of 234 line-km (flight line numbers 400801-401401 nonsuccessive), (2) Shellmound focus area in Mississippi with 250 m line spacing for a total of 485 line-km (flight line numbers 604501-608101 nonsuccessive), and (3) New Madrid Seismic Zone focus area in Missouri and Tennessee with variable line spacing for a total of 161 line-km (flight line numbers 710101-710401 nonsuccessive). 91-series lines are repeat test-lines flown periodically throughout the survey, with one repeat line established for each base station. 902- and 905-series lines are ~60 second high-altitude datasets collected pre- and post- flight, respectively, to evaluate the system out of ground-response. This data release includes minimally processed (raw) AEM data as supplied by CGG Canada Services, Ltd. (https://www.sciencebase.gov/catalog/item/5f4e951882ce4c3d1233cb7d), the fully processed (downsampled by averaging) sounding data (https://www.sciencebase.gov/catalog/item/5f4e953482ce4c3d1233cb82), and inverted resistivity depth sections along all flight lines (https://www.sciencebase.gov/catalog/item/5f4e954682ce4c3d1233cb84), as well as unprocessed and processed (following International Atomic Energy Agency Technical Report procedures) radiometric data as supplied by CGG Canada Services, Ltd. (https://www.sciencebase.gov/catalog/item/5f4e951882ce4c3d1233cb7d). Data acquisition and minimal processing was conducted by CGG Canada Services, Ltd. and described in detail in the contractor's report. Digital data from production flights are provided in ASEG-GDF2 format, an ASCII format geophysical data standard that uses a self-describing collection of files to allow data to be automatically identified and read by a computer application. Data fields in the data file (.DAT) are defined in the associated definition file (.DFN). Please see the ReadME included in this data release for a description of how to interpret the .DFN files or visit https://www.aseg.org.au/sites/default/files/pdf/ASEG-GDF2-REV4.pdf for more information on the ASEG-GDF2 standard.

Airborne electromagnetic (AEM), magnetic, and radiometric data were acquired September 2021 to January 2022 along 27,204 line-kilometers (line-km) over the Mississippi Alluvial Plain (MAP), Mississippi Embayment, and Gulf Coastal Plain. Data were acquired by Xcalibur Multiphysics (Canada), Ltd. with three different airborne sensors: the 30Hz TEMPEST time-domain AEM instrument that is used to map subsurface geologic structure at depths up to 300 meters (m) depending on the subsurface resistivity; a Scintrex CS-3 cesium vapor magnetometer that detects changes in deep (hundreds of meters to kilometers) geologic structure based on variations in the magnetic properties of different formations; and a Radiation Solutions RS-500 spectrometer that detects the abundance of natural radioelements potassium, uranium, and thorium in the upper 20-30 centimeters that is used to determine differences in soil constituents. The survey was flown at a nominal sensor flight height of 120 m above terrain with 300 and 600 km (nominal) spaced east-west flight lines. The main survey block covers 24,654 line-km. The Chicot aquifer focus area was surveyed along 360 line-km (flight numbers 2900101-2900421 nonsuccessive). The Mississippi River and the Atchafalaya River were surveyed along their center axes, covering 742 line-km (flight line numbers 6004001-6004003 and 5002001-5002002). Two separate inset grids were flown: (1) University of Memphis (UMemphis) focus area lines with 500 m line spacing for a total of 1260 line-km (flight line numbers 1000301-1030001 nonsuccessive), and (2) Hot Springs focus area with 350 m line spacing for a total of 188 line-km (flight line numbers 2001001-2027001 nonsuccessive). 91-series lines are repeat test-lines flown periodically throughout the survey, with one repeat line established for each base station. 901- and 904-series lines are flown under standard survey conditions with the transmitter on and the receiver off to evaluate the noise contribution from the acquisition system pre- and post- flight, respectively. 902- and 905-series lines are ~60 second high-altitude datasets collected to evaluate the system out of ground-response pre- and post- flight, respectively. 903-series lines are 30-40 second 'swoop' datasets to confirm correct operation of the system during variable pitch manoeuvres. 906-series lines are flown under standard survey conditions with the transmitter off and the receiver on to evaluate the ambient noise in the system. AEM data were inverted using 1-D inversion to produce models of electrical resistivity along flight paths.