This dataset captures in digital form the results of previously published U.S. Geological Survey (USGS) Water Mission Area studies related to water resource assessment of Cenozoic strata and unconsolidated deposits within the Mississippi Embayment and the Gulf Coastal Plain of the south-central United States. The data are from reports published from the late 1980s to the mid-1990s by the Gulf Coast Regional Aquifer-System Analysis (RASA) studies and in 2008 by the Mississippi Embayment Regional Aquifer Study (MERAS). These studies, and the data presented here, describe the geologic and hydrogeologic units of the Mississippi embayment, Texas coastal uplands, and the coastal lowlands aquifer systems, south-central United States. The Mississippi embayment, Texas coastal uplands, and coastal lowlands aquifer systems underlie about 487,000 km2 in parts of Alabama, Arkansas, Florida, Illinois, Kentucky, Louisiana, Mississippi, Missouri, Tennessee, and Texas from the Rio Grande on the west to the western part of Florida on the east. The previously published investigations divided the Cenozoic strata and unconsolidated deposits within the Mississippi Embayment and the Gulf Coastal Plain into 11 major geologic units, typically mapped at the group level, with several additional units at the formational level, which were aggregated into six hydrogeologic units within the Mississippi embayment and Texas coastal uplands and into five hydrogeologic units within the Coastal Lowlands aquifer system. These units include the Mississippi River Valley alluvial aquifer, Vicksburg-Jackson confining unit (contained within the Jackson Group), the upper Claiborne aquifer (contained within the Claiborne Group), the middle Claiborne confining unit (contained within the Claiborne Group), the middle Claiborne aquifer (contained within the Claiborne Group), the lower Claiborne confining unit (contained within the Claiborne Group), the lower Claiborne aquifer (contained within the Claiborne Group), the middle Wilcox aquifer (contained within the Wilcox Group), the lower Wilcox aquifer (contained within the Wilcox Group), and the Midway confining unit (contained within the Midway Group). This dataset includes structure contour and thickness data digitized from plates in two reports, borehole data compiled from two reports, and a geologic map digitized from a report plate. Structure contour and thickness maps of hydrogeologic units in the Mississippi Embayment and Texas coastal uplands had been previously digitized by a USGS study from georeferenced images of altitude and thickness contours in USGS Professional Paper 1416-B (Hosman and Weiss, 1991). These data, which were stored on the USGS Water Mission Area’s NSDI node, were downloaded, reformatted, and attributed for present dataset. Structure contour maps of geologic units in the Mississippi Embayment and Texas coastal uplands were digitized and attributed from georeferenced images of altitude and thickness contours in USGS Professional Paper 1416-G (Hosman, 1996) for this data release. Borehole data in this data release include data compiled for USGS Gulf Coast RASA studies in which a scanned version of a USGS report (Wilson and Hosman, 1987) was converted through optical character recognition and then manipulated to form a data table, and from borehole data compiled for the subsequent MERAS study (Hart and Clark, 2008) where an Excel workbook was downloaded and manipulated for use in a GIS and as part of this dataset. The digital geologic map was digitized from Plate 4 of USGS Professional Paper 1416-G (Hosman, 1996) and then attributed according to the USGS National Cooperative Geologic Mapping Program’s GeMS digital geologic map schema. The digital dataset a digital geologic map with contacts and faults and geologic map polygons distributed as separate feature classes within a geographic information system geodatabase. The geologic map database is a digital representation of the geologic compilation

Digital surfaces and thicknesses of selected hydrogeologic units of the Floridan aquifer system were developed to define an updated hydrogeologic framework as part of the U.S. Geological Survey Groundwater Resources Program. This feature class contains alluvial areas of major streams and a buffered area around medium sized streams that may also have alluvial materials. Geologic maps and buffered streams were used in the construction of this layer.

Digital surfaces and thicknesses of selected hydrogeologic units of the Floridan aquifer system were developed to define an updated hydrogeologic framework as part of the U.S. Geological Survey Groundwater Resources Program. This feature class contains alluvial areas of major streams and a buffered area around medium sized streams that may also have alluvial materials. Geologic maps and buffered streams were used in the construction of this layer.

Digital surfaces and thicknesses of selected hydrogeologic units of the Floridan aquifer system were developed to define an updated hydrogeologic framework as part of the U.S. Geological Survey Groundwater Resources Program. This feature class contains alluvial areas of major streams and a buffered area around medium sized streams that may also have alluvial materials. Geologic maps and buffered streams were used in the construction of this layer.

This dataset includes isopach contours showing altitude of freshwater of the Carrizo-Wilcox aquifer, control points used to construct the freshwater isopach contours, isopach contours showing altitude of top of the Carrizo-Wilcox aquifer, wells used to construct cross sections and isopach contours, hydrogeologic cross section H-H' through S-S' lines, isopach contours showing altitude of the base of the Carrizo-Wilcox aquifer, well points used to construct base isopach contours, isopach contours showing thickness of the Carrizo-Wilcox aquifer, and wells used to construct thickness isopach contours. Datasets are shown in figures of the larger body of work "Hydrogeologic framework of the Red River alluvial aquifer and the Carrizo-Wilcox aquifer in northwestern Louisiana" (Hays and others, 2021).

Digital surfaces and thicknesses of selected hydrogeologic units of the Floridan aquifer system were developed to define an updated hydrogeologic framework as part of the U.S. Geological Survey Groundwater Resources Program. This feature class contains a polygon showing the extent of the Boulder Zone in southern Florida (from Miller, 1986).

Scientists from the U. S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center investigated the sedimentary and geochemical properties of the lower reaches of the Pearl River in eastern Louisiana by collecting estuarine, riverine and marsh sediments. This was done in order to increase understanding of the region's environmental history, quantify the deposition associated with Hurricane Katrina, identify the subsequent changes in the deposited sediments and assess the effects of this deposition on marsh sustainability. To this end, the group obtained long sediment cores, shovel-dug sediment slabs and marsh and riverine channel/estuarine surface samples from a north-south transect along the river edge from the low-salinity bottomland hardwood forest through Lake Borgne, and a west-east transect near the coast, during field work conducted in September 2015.

Digital surfaces and thicknesses of selected hydrogeologic units of the Floridan aquifer system were developed to define an updated hydrogeologic framework as part of the U.S. Geological Survey Groundwater Resources Program. This feature class contains points representing well cluster sites used to evaluate vertical head gradients in the aquifer system. Individual well identifiers are not show

Digital surfaces and thicknesses of selected hydrogeologic units of the Floridan aquifer system were developed to define an updated hydrogeologic framework as part of the U.S. Geological Survey Groundwater Resources Program. This feature class contains points representing well cluster sites used to evaluate vertical head gradients in the aquifer system. Individual well identifiers are not show

Digital surfaces and thicknesses of selected hydrogeologic units of the Floridan aquifer system were developed to define an updated hydrogeologic framework as part of the U.S. Geological Survey Groundwater Resources Program. This feature class contains wells used in the cross sections.