There are 11 US Post Offices in Platte County serving a total of 62,980 residents equating to 5,725 residents per post office. It's estimated that approximately 100,523 packages are handled across the 11 county post offices annually. Platte County is a county located in the northwestern portion of the U.S. state of Missouri. As of the 2010 census, the population was 89,322. Its county seat is Platte City. The county was organized December 31, 1838 from the Platte Purchase, named for the Platte River. (Platte is derived from the French word for a low, shallow, or intermittent stream.) Platte County is part of the Kansas City, MO-KS Metropolitan Statistical Area and contains some of the city's northwestern suburbs. Kansas City International Airport is located in the county, approximately one mile west of Interstate 29 between mile markers 12 and 15. The land for the airport was originally in an unincorporated portion of Platte County before being annexed by Platte City, and eventually Kansas City."