Cedar City's rich deposits of iron ore were first recorded by Spanish explorers Dominguez and Escalante in 1776. In 1850, Mormon leader Brigham Young sent a group of colonists to mine these deposits to provide needed iron implements to western settlers. This colonization became known as the Iron Mission. In 1923, Union Pacific constructed a rail line that allowed increased production, but by the mid 1980s foreign competition and domestic tax issues led to the closure of the mines. This area still holds one of the nation's richest deposits of iron.