There are 3 US Post Offices in Crittenden County serving a total of 8,450 residents equating to 2,817 residents per post office. It's estimated that approximately 13,487 packages are handled across the 3 county post offices annually. Crittenden County is a county located in the U.S. state of Kentucky. At the 2010 census, the population was 9,315. Its county seat is Marion. The county was formed in 1842 and named for John J. Crittenden, senator and future Governor of Kentucky. It is a prohibition or dry county."