I have just begun extensive work on checking all amateur radio stations from the US to find out which county station is coming from. I have about 3,700 QSO registered in my log to be checked - it will take som time to go through everything and the page will be updated continuously.
I have not yet applied for the basic award where you have to have 500 confirmed counties.
Number of worked counties:602
Number of confirmed counties with QSL or eQSL (excluding LoTW):396 (Updated on November 25, 2019)
Click on the image to see a larger version of the map