There are 5 US Post Offices in Nicollet County serving a total of 31,897 residents equating to 6,379 residents per post office. It's estimated that approximately 50,911 packages are handled across the 5 county post offices annually. Nicollet County is a county located in the U.S. state of Minnesota. It was named for French geographer Joseph N. Nicollet. As of the 2010 census, the population was 32,727. Its county seat is St. Peter. Nicollet County is part of the Mankato\u2013North Mankato, MN Metropolitan Statistical Area."