County Business Patterns, 2006
U.S. Census Bureau.
Available online.
Most recent edition of annual data on the "total number of establishments, mid-March employment, first quarter and annual payroll, and number of establishments by nine employment-size classes by detailed industry for all counties in the United States and the District of Columbia." Site also includes access by metropolitan areas and ZIP Codes.
Links will be maintained in several locations in our Web site, including here.