Glenn County as of the 2010 census, the population was 28,122. The county seat is Willows. It is located in California's Central Valley. Glenn County was formed in 1891 from parts of Colusa County. It was named for Hugh J. Glenn, who was the largest wheat farmer in the state during his lifetime, and a man of great prominence in political and commercial life in California. According to the U.S. Census Bureau, the county has a total area of 1,327 square miles of which 1,314 square miles is land and 13 square miles (1.0%) is water.