There are 7 US Post Offices in Labette County serving a total of 21,225 residents equating to 3,032 residents per post office. It's estimated that approximately 33,877 packages are handled across the 7 county post offices annually. Labette County (county code LB) is a county located in the U.S. state of Kansas. As of the 2010 census, the county population was 21,607. Its county seat is Oswego, and its most populous city is Parsons. The county was named after LaBette creek, the 2nd largest creek in the county, which runs roughly NNW-SSE from near Parsons to Chetopa. The creek in turn was named after French-Canadian fur trapper Pierre LaBette who had moved to the area, living along the Neosho River, and marrying into the Osage tribe in the 1830s and 1840s."