This resource, from the U.S. Department of Commerce and the United States Census Bureau, provides access to data about the United States, Puerto Rico and the Island Areas. The data in American FactFinder come from several censuses and surveys starting in 1990.
Good starting place for 2010 Census data
American Housing Survey (AHS)
Data on the nation's housing from Bureau of the Census for the Department of Housing and Urban Development. The survey is the most comprehensive national housing survey in the United States, covering a wide range of subjects on housing.
Historical and Specialized Data
Decennial Census of Population and Housing
Historic US Censuses from 1790 to date.
1990 Census Gateway
Good starting place for 1990 Census data.
Census 2000 Gateway
Good starting place for 2000 Census data.
Measuring America: The Decennial Censuses from 1790-2000
Images and descriptions of the questionnaires used in each census.
Web-based service that provides interactive search-and-display access to the following databases: Building Permits; County Business Patterns; Zip Code Business Patterns; International Trade Data; Non-employer Statistics; USA Counties; Census Tract Street Locator; Detailed Occupation by Race, Hispanic Origin & Sex; and Public Law 94-171 Data.
IPUMS (ntegrated Public Use Microdata Series)
University of Minnesota site hosting a variety of Census Bureau's IPUMS data series.
National Historical Geographic Information System
Provides free, aggregate census data and GIS-compatible boundary files for the US from 1790 to 2015. Sponsored by the Minnesota Population Center.
State and Local Data
New Hampshire State Data Center - NH Office of Energy and Planning
Provides direct access to numerous files (data library) that contain data about New Hampshire.
State of the Cities Data System (SOCDS)
From HUD, provides data for individual Metropolitan Areas, Central Cities, and Suburbs.