There are 15 US Post Offices in Henry County serving a total of 50,534 residents equating to 3,369 residents per post office. It's estimated that approximately 80,658 packages are handled across the 15 county post offices annually. Henry County is a county located in the U.S. state of Indiana. As of 2010, the population was 49,462. The county seat is New Castle. Henry County is the main setting of the novel Raintree County by Ross Lockridge, Jr.."