There are 2 US Post Offices in Caldwell County serving a total of 12,987 residents equating to 6,494 residents per post office. It's estimated that approximately 20,729 packages are handled across the 2 county post offices annually. Caldwell County is a county located in the U.S. state of Kentucky. As of the 2010 census, the population was 12,984. Its county seat is Princeton. The county was formed in 1809 from Livingston County, Kentucky and named for John Caldwell, who participated in the George Rogers Clark Indian Campaign of 1786 and was the second lieutenant governor of Kentucky. Caldwell was a prohibition or dry county until 2013, when the citizens voted to lift the ban."