Eagan, Tennessee  Eagan is an unincorporated community in Claiborne County and Campbell County, Tennessee, in the Cumberland Mountains of the southeastern United States. It lies along State Route 90 just west of Clairfield in the Clearfork Valley. A former coal mining town, Eagan was likely named for either a mining company official or a minister. Eagan is home to several small business, churches, and a community center, the Clearfork Community Institute. It also has its own post office, with ZIP code 37730.