The County of Beaver was created in 1886 by an act of the Legislature of the Territory of Utah. Because of the Mountain Meadow Massacre and Indian raids on the settlements, Fort Cameron was established in 1873 by United States troops. The post, two miles east of Beaver, was maintained until 1882. The buildings were then used as an LDS Church school, and later became the site of the Murdock Academy.
The opening of the Newhouse and Frisco Mining Districts had a tremendous impact on the development of Beaver County. The mining camps are now ghost towns, but some of their attendant developments remain key factors today. The mining industry influenced the expansion of a railroad into central and southern Utah. The Utah Central Railroad tracks were laid as far south as Milford by 1880. The Utah Southern and Utah Southern Extension roads were acquired in 1900 by the San Pedro, Los Angeles, and Salt Lake Route, which in 1905 completed its line to southern California, and in 1921 was incorporated into the Union Pacific system.