Clement Clark and his son, Richard who married Clementina Elder came to KY from the Emmettsburg, MD area. That is in Western Maryland up above Frederick almost to the PA border. Whether that means they came from PA in lieu of MD I cannot say. My wife says we have quite a bit of data on the Elders so will try to take a look at that.

I note that in the 1795 and 1800 Tax Rolls for Nelson County, there are no Elder's listed and Clement is listed in both.
In 1805 Clement and Richard are both listed and Thomas Elder is listed for the first time. Richard married Clementina in 1806 in Nelson Co, Ky by S. T. Badin.

Charley