There are 13 US Post Offices in Kosciusko County serving a total of 62,499 residents equating to 4,808 residents per post office. It's estimated that approximately 99,755 packages are handled across the 13 county post offices annually. Kosciusko County is a county located in the U.S. state of Indiana. Census 2010 recorded the population at 77,358. The county seat is Warsaw. The county was formed in 1836. It was named after the Polish general Tadeusz Ko\u015bciuszko who served in the American Revolutionary War and then returned to Poland. The county seat is named after Warsaw, the capital of Poland."