Changes in boundaries and borders as the U.S. expanded

Check out the interactive maps available for your state. One great site is the Atlas of Historical County Boundaries, where I was able to find this early map of Kentucky, before all 120 counties were established.
This tool will show you how the county lines shifted as new counties were added, from the time Kentucky was actually a county of Virginia to when it first became a state in 1792, and all the way up to the year the last county was created. Visit https://digital.newberry.org/ahcb/.