The National Historical Geographic Information System is a project to create and freely disseminate a database incorporating all available aggregate census information for the United States between 1790 and 2000. The data being incorporated into NHGIS covers social and economic topics, such as income, education, labor, housing, elections, religion, and agriculture. When complete, NHGIS will provide data for various levels of geography.
Free registration required for access.
Project information -- User notes -- Data -- Documentation.