There are a lot of US Counties! To be exact, there are 3,006 US counties according the US Census Bureau. I am collecting them one at a time on amateur radio with confirmed contacts tracked on qrz.com as part of United States Counties Award.
So far, my strategy is to simply make random QSOs without regard to County location. That will likely change if I ever decide I want to fill County gaps and make contacts with stations in less populated Counties.
Today I hit 800 confirmed US Counties out of 3,006 which is 26.6%. Only 2,206 US Counties to go! I have confirmed contacts with all Counties in three States.
Good DX and 73, NJ2X