I went to this website (USGS board on geographic names), downloaded each state's information and then filtered the rows with "county" in the place name. Each state's URL can be programatically manipulated easily.
Dothub provides a list of US Business entities parsed from official registries https://www.dolthub.com/repositories/dolthub/us-businesses/data/master
Just use the following SQL query.
where state_registered = 'ME'
Disclaimer: I have no relations with DoltHub, Inc.