United State Census
Summary tables focusing on age, sex, households, families, and occupied housing units; general demographic profiles; and redistricting data for state legislature redistricting and congressional apportionment. The American Factfinder is a good place to start.
CensusScope is an easy-to-use tool for investigating U.S. demographic trends. Includes charts, maps, and ranking for national, state, metro, and county data from the 2000, 1990, and 1980 censuses (and sometimes earlier). Browsable from many data entry points.
Latest U.S. Census "data on racial and ethnic populations in the United States." Features browsable facts and statistics on Black/African American, Hispanic/Latino, Asian/Pacific Islander, and American Indian/Alaska Native populations in the United States.
State & Country Quick Facts
Census information for national, state, and county levels. Tables include People Facts, Business Facts, and Geographical Facts (land area and density). People Facts include recent population estimates; racial, age, and gender breakouts; high school and college graduates; households; children under the poverty level; etc. Business Facts include retail sales, minority- and women-owned businesses, building permits, etc.