Gage County is a county in the U.S. state of Nebraska. As of the 2020 United States Census, the population was 21,704. Its county seat is Beatrice. The county was created in 1855 and organized in 1857. It was formed from land taken from the Otoe in an 1854 treaty. The county was named for William D. Gage, a Methodist minister who served as the first chaplain of the Nebraska Territorial Legislature.