Although the early settlers planted crops and grazed livestock, the county prospered in the nineteenth century because of a unique blend of mining, transportation, and trade in addition to farming. The , located northwest of Minersville, may have been the first mine opened in Utah (1858). Lead was smelted and shipped to Salt Lake City
to make ammunition. Many claims were staked and mining districts organized in the 1870s. The fabulous Horn Silver Mine was discovered in 1875, and the nearby town of Frisco
, a wild boomtown, was founded in 1876. The Horn attracted famous investors such as J. Pierpont Morgan.
Milford was founded in 1870 by livestock growers and became an important transportation center in May 1880 when the Utah Southern Railroad reached the town. The line was extended to Frisco a month later. Both ore and livestock were shipped from the town to Salt Lake, and Milford was also a forwarding point for freight. Horse and wagon teams carried freight from Milford to southern Utah, to northern Arizona, and to mining camps in Nevada. In Beaver City, the Beaver Woolen Mills, which operated from the 1870s to the turn of the century, found Frisco an important market for its products, especially blankets. The Beaver co-op store, reportedly the largest mercantile establishment south of Salt Lake City, opened in 1872 and profited from mining and transportation activity.
The Frisco mining boom lasted only a decade. In the early twentieth century the Cactus Mine near the town of Newhouse, west of Frisco, produced gold, silver, copper, and other minerals. In the 1980s the county's geothermal resources began to be tapped when an electric power generating plant using natural steam was built northeast of Milford.
Miriam B. Murphy