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Atlas of Historical County Boundaries Returns!

The Atlas of Historical County Boundaries is an AMAZING resource for US genealogical research - offline for nearly two years, it is now back and ready to use!

Now this is BIG NEWS for genealogy and family history enthusiasts! The Atlas of Historical County Boundaries is back at The Newberry Library website and functioning in beta mode! Click here to access.

What Is the Atlas of Historical County Boundaries?

From the ACHBP website: “A project of the William M. Scholl Center for American History and Culture at The Newberry Library in Chicago, the Atlas of Historical County Boundaries is a powerful historical research and reference tool in electronic form. 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.”

How to Use the Atlas of Historical County Boundaries

Very often, when I am researching a new location, I’m not sure if my ancestor’s town is located in a specific county. County boundaries changed especially from statehood to the present day. 

So if I have my great-great-great grandmother Catherine Sullivan listed as born in Lewis County, New York, I may need to see whether or not Lewis County actually existed at that time – it may still have been part of Oneida County.

Simply select a time period aligning with your research and see what the county looked like at that time. One important change to AHCBP website is the ability to enter an exact date – this was a feature of the old site before it was revamped.

In addition, users can look at a specific timeline of change for a county and also download files for use in Google Earth and other programs.

©2017, copyright Thomas MacEntee. All rights reserved.