Mille Lacs County is a county in the East Central part of the U.S. state of Minnesota. As of the 2020 census, the population was 26,459. Its county seat is Milaca. The county was founded in 1857, and its boundary was expanded in 1860. Mille Lacs County is included in the Minneapolis-St. Paul Metropolitan Statistical Area. A portion of the Mille Lacs Indian Reservation is in the county.