Atlas of historical county boundaries


Presents maps, text, and data about the creation and all subsequent changes (dated to the day) in the size, shape, and location of every U.S. county in the 50 states as well as the District of Columbia.

About this resource:

First launched in 2010, the Atlas represents more than 20 years of work compiling U.S. county lines from research in state laws and other primary sources. Offers comprehensive information for counties in all 50 states as well as the District of Columbia. Includes non-county areas, unsuccessful authorizations for new counties, changes in county names and organization along with the temporary attachments of non-county areas and unorganized counties to fully functioning counties.

This resource appears in the following subjects:
This resource is open to the general public.