There are 10 US Post Offices in Carlton County serving a total of 37,013 residents equating to 3,701 residents per post office. It's estimated that approximately 59,077 packages are handled across the 10 county post offices annually. Carlton County is a county located in the State of Minnesota. As of the 2010 census, the population was 35,386. Its county seat is Carlton. A portion of the Fond du Lac Indian Reservation is in the county. The county was formed in 1857 and organized in 1870. Carlton County is included in the Duluth, MN-WI Metropolitan Statistical Area."