Colorado became a state on August 1, 1876, as the 38th state of the United States. The proclamation of statehood was signed by President Ulysses S. Grant. It became a state the same year the U.S. celebrated its 100th birthday, receiving the name Centennial State.
Colorado was originally part of Utah, New Mexico, Nebraska and Kansas territories. Through the Louisiana Purchase, the U.S. acquired Colorado's eastern part in 1803. The U.S. later acquired the whole of Colorado after the Mexican War ended in 1848 through the Treaty of Guadalupe Hidalgo. The land was mostly occupied by Indians, including the Ute, Cheyenne and Arapaho, among others.