Map Resources Online: Databases and Data Sources

"This dataset represents the GIS Version of the Public Land Survey System including both rectangular and non-rectangular surveys. The primary source for the data is cadastral survey records housed by the BLM supplemented with local records and geographic control coordinates from states, counties as well as other federal agencies such as the USGS and USFS. The data has been converted from source documents to digital form and transferred into a GIS format that is compliant with FGDC Cadastral Data Content Standards and Guidelines for publication."

From the USDA Economic Research Service

"On the BTS Open Data site, browse geospatial data that is part of the BTS National Transportation Atlas Database (NTAD) product. NTAD is a set of nationwide geographic databases of public spatial information for transportation facilities and networks; flows of people, goods, vehicles, and craft over the transportation networks; and social, economic, and environmental conditions that affect or are affected by the transportation networks." Allows downloads of complete datasets.

"The Gridded Population of the World (GPW) collection [...] models the distribution of human population (counts and densities) on a continuous global raster surface. Since the release of the first version of this global population surface in 1995, the essential inputs to GPW have been population census tables and corresponding geographic boundaries. The purpose of GPW is to provide a spatially disaggregated population layer that is compatible with data sets from social, economic, and Earth science disciplines, and remote sensing."

Includes access to various datasets as well as U.S. Census data

Free, downloadable GIS data for the Shawnee National Forest in in the form of shapefiles or layers.

TopoView highlights one of the USGS's most important and useful products, the topographic map.

Presents instructions and examples on how to locate and interact with topographic maps online in the USGS database.

"An open access archive of spatial demographic datasets for Central and South America, Africa and Asia to support development and health applications."