<P> Statehood was regarded as fairly imminent, as during the run - up to the 1864 presidential election the Republican--controlled Congress was actually eager to get two more Republican senators and three more electoral votes for President Lincoln's re-election bid . Territorial Governor John Evans persuaded Congress to adopt an enabling act, but a majority of the 6,192 Coloradoans who voted, in a population of around 35,000, turned down the first attempt at a state constitution and the second attempt at statehood . Later, at the end of 1865, territorial ambitions for statehood were thwarted again, this time by a veto by President Andrew Johnson . Statehood for the territory was a recurring issue during the Ulysses Grant administration, with Grant advocating statehood against a less willing Congress during Reconstruction . </P> <P> The Colorado War (1863--1865) was an armed conflict between the United States and a loose alliance among the Kiowa, Comanche, Arapaho, and Cheyenne nations of Native Americans (the last two were particularly closely allied). The war was centered on the Eastern Plains of the Colorado Territory and resulted in the removal of these four Native American peoples from present - day Colorado to present - day Oklahoma . The war included a particularly notorious episode in November 1864 known as the Sand Creek Massacre . The battle, initially hailed by the U.S. press as a great victory, was later learned to be one of genocidal brutality . The resulting hearings in the United States Congress regarding the malfeasance of the U.S. Army commander, John Chivington, were a watershed in the white views of the Indian Wars at the close of the American Civil War . In 1868 the U.S. Army, led by George Armstrong Custer, renewed the conflict against the Arapaho and Cheyenne at the Battle of Washita River . </P> <P> The United States Congress passed an enabling act on March 3, 1875, specifying the requirements for the Territory of Colorado to become a state . On August 1, 1876 (28 days after the Centennial of the United States), U.S. President Ulysses S. Grant signed a proclamation admitting the state of Colorado to the Union as the 38th state and earning it the moniker "Centennial State". The borders of the new state coincided with the borders established for the Colorado Territory . </P> <P> Women won the right to vote in Colorado in 1893 . Colorado was the first state in the union to grant this right to women through a popular election . (Wyoming approved the right of women to vote in 1869 through a vote of the territorial legislature .) </P>

When did colorado become part of the united states