There are 10 US Post Offices in Montgomery County serving a total of 36,252 residents equating to 3,625 residents per post office. It's estimated that approximately 57,862 packages are handled across the 10 county post offices annually. Montgomery County (county code MG) is a county located in the U.S. state of Kansas. As of the 2010 census, the county population was 35,471. Its county seat is Independence, and its most populous city is Coffeyville."