What county holds the records for your research? Use the Atlas of Historical County Boundaries from the Newberry Library to browse by state, then date. The Atlas presents in maps and text complete data about the creation and all subsequent changes (dated to the day) in the size, shape, and location of every county in the fifty United States and the District of Columbia. It also includes non-county areas, unsuccessful authorizations for new counties, changes in county names and organization, and the temporary attachments of non-county areas and unorganized counties to fully functioning counties. The principal sources for these data are the most authoritative available: the session laws of the colonies, territories, and states that created and changed the counties. See "About the Project" and "Using the Atlas" for more details.