Fairfield was settled in 1855 by John Carson, William Carson, David Carson, William Beardshall, and John Clegg, and a rock fort four rods square was erected in 1856-57 with its entrance at the southeast corner. In 1860 the population, including soldiers, was 7,000, making it Utah's third largest city. Camp Floyd, adjoining Fairfield on the south and west, was established July 4, 1858 by BVT. Brig. Gen. Albert Sidney Johnston and the Utah Expeditionary Forces numbering about 3,000 men. Col. Phillip St. George Cooke succeeded in command March 1, 1860 and changed the name to Fort Crittenden on February 6, 1861, before the post was abandoned in July 1861. An Overland stage station established in 1859 operated until 1868, and a Pony Express station operated there from April 3, 1860 to October 26, 1861. Camp Floyd, later Fort Crittenden, served as a way station for the Pony Express, provided troops to protect against Indian attack, and kept the trail open for the Pony Express and stage line.