Long ago I noticed the “map view” with “clustering” on and off settings that is an option for Relative Finder at 23andMe. Here is the latest update without clustering, each match as a single purple marker, with a geographical breakdown of locations:
This is interesting about the broad geographical range of the hundreds of matches, and suggestive about migration patterns of the last three centuries. But I just noticed the option to narrow the map down to matches so close as to measure as 3rd cousins or closer. This brought the total down to 17 from 590, and the map was much more specific geographically. Here we find a very impressive reliability for autosomal matching. There can be no question about which county was home to more of my 19th century ancestors than any other when you see this map. Three outliers in Connecticut, Texas, and Tennessee were cropped out to focus on main cluster. The blue circle of nine close matches is over Bertie County.