An online database of architectural and historical information and images for 35,000+ structures, 110,000 images+ images and maps and biographies of 5,000+ architects in the 5 county region around Philadelphia. Development was a collaboration between private, academic, and public entities led by the Athenæum of Philadelphia.

Historic sites listed on the Philadelphia Register. Data was updated by the Philadelphia City Planning Commission in July 2017. The public should confirm a property’s historic status by contacting the Historical Commission at 215-686-7660. You can also download a dataset of the [Historic districts](https://www.opendataphilly.org/datasets/philadelphia-registered-historic-districts).

PhillyHistory.org is an online database of historic photographs and maps from the Philadelphia City Archives and four additional area institutions. A project of the City of Philadelphia Department of Records, the database contains images dating back to the 1850s and can be searched by geographic criteria such as address, intersection, place name, and neighborhood as well as keyword, date, collection, topics, and other criteria. Images and maps are associated with a location using the database's geocoding feature. Users can create a free account to save images, bookmark searches, and submit error reports.

To map older streets with historical value in the City of Philadelphia.

Mid-century modern architecture and buildings of the recent past are enjoying a resurgence of appreciation and interest nationwide, but here in Philadelphia, our eclectic collection of postwar buildings is often overlooked. To help identify and celebrate these emerging landmarks, the Preservation Alliance is compiling a list of notable structures built within the city between 1945 and 1980. The inclusion of a building in this inventory does not imply endorsement of it for designation or other purposes, nor does its absence imply a lack of significance. Rather, the list is meant to illustrate the breadth and depth of design from an era often overshadowed by earlier periods and styles.

Founded as William Penn's "Holy Experiment," Philadelphia has a centuries-long history of fostering and constructing prominent houses of worship throughout the city. In recent decades, as congregations face declining membership and shifting neighborhood demographics, these historically- and architecturally-significant properties have often suffered from deferred maintenance, insensitive alterations, and partial or complete demolition. Advocacy organizations like the Preservation Alliance for Greater Philadelphia and Partners for Sacred Places have focused on this issue for years, highlighting the threats to Philadelphia's neighborhoods and communities if these structures continue to be abandoned or lost. Over the summer of 2011, in order to more fully understand and address the issue, the Preservation Alliance partnered with Philadelphia Historical Commission and Partners for Sacred Places to develop a comprehensive index of historic churches covering the entire city. Compiling, verifying, and updating data from a number of different sources, University of Pennsylvania graduate student Molly Lester assembled a database which includes every purpose-built house of worship constructed in the city before 1960. Data elements include: current congregation, original congregation, address, year of construction, original architect and whether or not the build is on the Philadelphia or National Historic Registers.

Pittsburgh Historic Districts

Basemaps of the Philadelphia area, including from the Department of Records.

This EnviroAtlas dataset portrays the total number of historic places located within each Census Block Group (CBG). The historic places data were compiled from the National Register of Historic Places, which provides official federal lists of districts, sites, buildings, structures and objects significant to American history, architecture, archeology, engineering, and culture. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).