There are 7 US Post Offices in Sibley County serving a total of 13,695 residents equating to 1,956 residents per post office. It's estimated that approximately 21,859 packages are handled across the 7 county post offices annually. Sibley County is a county located in the U.S. state of Minnesota. As of the 2010 census, the population was 15,226. Its county seat is Gaylord. Sibley County is included in the Minneapolis-St. Paul-Bloomington, MN-WI Metropolitan Statistical Area."