There are 6 US Post Offices in Bartholomew County serving a total of 50,644 residents equating to 8,441 residents per post office. It's estimated that approximately 80,833 packages are handled across the 6 county post offices annually. Bartholomew County is a county located in the U.S. state of Indiana As of 2010, the population was 76,794. The county seat is Columbus. The county was determined by the U.S. Census Bureau to include the mean center of U.S. population in 1900. Bartholomew County is part of the Columbus, Indiana Metropolitan Statistical Area.