Good Places to Start (more in other tabs)
- ESRI Data & Maps Layers covering the USA, international areas, and the entire world (Duke Only)
- Census Bureau TIGER Products Includes the TIGER/Line Shapefile boundaries for Census geographies.
- The National Map Small-Scale Data Download From the US Geological Survey (layers formerly at The National Atlas site)
- USDA Geospatial Data Gateway US Dept. of Agriculture
- DATA.gov US Federal agency data; can limit to geospatial data
- NC OneMap North Carolina GIS data
- Durham County, NC, GIS layers (Duke Only)
- Duke GIS layers (Duke Only)
Data for History
- Euratlas Historical Political Boundaries of Europe (Duke Only)
- NHGIS US boundary files for 1790 through 2010
- GeoCommons Various GIS layers and geospatial data uploaded by anyone. Hit-or-miss, but you might find anything.