In honor of this 4th of July, here’s an animation of county boundary formation in the United States starting in 1629 up through the present day, derived from the Historical U.S. Counties on Google Maps tool:
And here’s a close-up focusing on the northeastern U.S.:
Explore all of the historical county boundary lines in your area of interest in great detail using the Historical U.S. Counties on Google Maps tool. I’ll leave you with this example centered on Independence Hall in Philadelphia, 4 July 1776:
Wishing you and your families and friends a happy and peaceful 4th!