Fillmore County is a county located in the U.S. state of Minnesota. As of 2000, the population was 21,122. Its county seat is Preston.

According to the U.S. Census Bureau, the county has a total area of 862 square miles (2,233 km²), of which 861 square miles (2,231 km²) is land and 1 square mile (2 km²) (0.10%) is water.

Official Fillmore County website