County Business Patterns
County, state, and national level business data including number of establishments, payroll, number of employees and number of establishments by size class for 2 digit SIC industry groupings.
County and City Databook
A wide variety of demographic, social and economic variables for counties, cities, places and states.
Collections of Statistics/ Census Data/ Demographics
American FactFinder U. S. Census Bureau.
Basic facts for counties or municipalities, including total population; sex and age breakdowns; race breakdowns; household relationship data; households by type; housing occupancy; and housing tenure.
U. S. Census Bureau
The main page for census information. You can also get to census data from the FedStats and State Data Center links, above.