Initial Publication Date: September 7, 2010

Links to other GIS data sources

ESRI TIGER Census 2000 data interface
National Historical Geographic Information System-aggregate census data and GIS-compatible boundary files for the United States between 1790 and 2000
United States Census Bureau TIGER
Data for Decision: Three part series (short) of Canada's Land Inventory Geo-Information System

Elevation & Benthic:
ASTER DEM-higher latitude than SRTM data (registration required–free)
Consortium for Spatial Information (CGIAR)-filled global 90m SRTM data
USGS CLICK LiDAR viewer-PA las files are being posted here but not complete
NOAA Digital Coast–coastal and nearshore benthic data sets including LiDAR
Open Topography LiDAR portal
Puget Sound LiDAR Consortium-LiDAR data for Washington and Oregon
Digital Elevation Data

NASA Goddard Space Flight Center Global Change Master Directory
University of Maryland Global Land Cover Facility–LANDSAT and other satellite imagery

Maps-historic and otherwise:
Ask the Cartographer
ArcGIS online Standard Map collection (free for non-commercial use)
new ArcGIS resource center (Groups > ESRI Data and Maps, 17 pages of data)
David Rumsey historical map collection
East View Geospatial-great source for hard to find geologic maps-will scan and georeference from their collection
Historical GIS Boston 1775
USGS Energy Resources maps
Physiographic Provinces of US map
Landsat Image Mosaic of Antarctica
Reed-Bush Geologic Map of US
King-Beikman Geologic Map of US
Geologic maps of all US states 
NASA Earth Observations 
Natural Earth 
World geologic map online viewer 

National EPA Geospatial data page
National Operational Hydrologic Remote Sensing Center
National Snow and Ice Data Center
USDA National Resources Conservation Service Geospatial Data Gateway
Color Brewer: Color selection tool for visualizing quantitative data out of Penn State 
STEM: Geospatial Technology Curriculum Page
ESRI GIS Education Community 
United Nations Environment Program 
World Clim - Global Climate Data 
NASA data, with lessons and some online analysis capabilities 
SHELDUS, U.S. hazard data set