NHGIS is a data portal for U.S. Census data in both tabular and geospatial formats. It provides access to summary statistics and GIS boundary files for population and agricultural censuses and other nationwide surveys from 1790 through the present. Alternatively, for a user-friendly online mapping interface connected to this same data see Social Explorer.
A source for free geospatial datasets covering the entire globe at small, large, and medium scales. Includes a variety of cultural and natural features as well as elevation and bathymetric basemaps.
Online application for locating and mapping US Census data and other demographic resources. Maps created on Social Explorer can be exported as images. To download the data itself in tabular and GIS formats see National Historical Geographic Information System (NHGIS).
The United States Geological Survey’s (USGS) geospatial data and maps website. Access to geospatial datasets for hydrography, elevation, wetlands and many other natural and cultural features. For an interactive map for finding data see the National Map Viewer.
"Presents in maps and text complete data about the creation and all subsequent changes (dated to the day) in the size, shape, and location of every county in the fifty United States and the District of Columbia." Available as interactive maps and shapefiles that can be downloaded for use with GIS software.
A comprehensive collection of geospatial data, apps and maps from the U.S. Department of Transportation. Use the National Transportation Atlas Database for access to geospatial datasets.
A center within Columbia University's Earth Institute, CIESIN provides an extensive gateway to data and other information focusing on human interactions in the environment. Provides a topic search as well as subject access to spatial and tabular data sets held by CIESIN or hosted on its web site.
USGS data portal for global remote sensing data from satellite and aerial photography.
From the EPA, map various types of environmental information, including air releases, drinking water, toxic releases, hazardous wastes, water discharge permits and Superfund sites. See also TOXMAP, from the National Library of Medicine.
U.S. Environmental Protection Agency (EPA) data catalog includes a wide variety of geospatial data.
Federated search platform for U.S. federal government geospatial data. Follow links to Apps & Services/Map Viewer for an interactive map interface for finding geospatial data.
Geospatial data portal for the New Jersey Office of GIS. A collection of state agency GIS data for the entire state.
New York state government’s geospatial data portal. Follow link to CUGIR, the Cornell University geospatial data repository for more state-wide datasets.
A free, open source, editable map of the world. Users can choose various layers, add notes, and share or export the maps they create.
Coverage: 1937-1942, 1967-1972
Collection of historical aerial photos produced by the predecessor to the U.S. Farm Service Agency, and hosted by the Pennsylvania Geological Survey.
A data portal which includes geospatial data created by various USDA agencies.
Using mapping application ArcGIS Online this web service provides satellite and aerial imagery for much of the world. Higher resolution imagery is available for the continental U.S. and parts of Europe. This imagery is not available for download but can be streamed to desktop GIS software for analysis or export.