There are 6 US Post Offices in Rush County serving a total of 3,189 residents equating to 532 residents per post office. It's estimated that approximately 5,090 packages are handled across the 6 county post offices annually. Rush County (standard abbreviation: RH) is a county located in the U.S. state of Kansas. As of the 2010 census, the county population was 3,307. The largest city and county seat is La Crosse."