Aitkin County is a county in the U.S. state of Minnesota. As of the 2020 census, the population was 15,697. Its county seat is Aitkin. Part of the Mille Lacs Indian Reservation is in the county. The county was created in 1857 and organized in 1871.

Pine County is a county in the U.S. state of Minnesota. As of the 2020 census, the population was 28,876. Its county seat is Pine City. The county was formed in 1856 and organized in 1872. Today, Pine County is the fastest growing county in the state.