There are 3 US Post Offices in Carroll County serving a total of 10,820 residents equating to 3,607 residents per post office. It's estimated that approximately 17,270 packages are handled across the 3 county post offices annually. Carroll County is a county located in the U.S. state of Kentucky. As of the 2010 census, the population was 10,811. Its county seat is Carrollton, Kentucky. The county was formed in 1838 and named for Charles Carroll of Carrollton, the last living signer of the Declaration of Independence. It is located at the confluence of the Kentucky and Ohio Rivers."