On December 12, 1919, Colorado became the 22nd state to ratify the 19th Amendment to the U.S. Constitution, which granted women the right to vote. Governor Shoup signed his approval of ratification a few days later, on December 15th.
The Amendment required 36 states to ratify it in order to pass. Illinois was the first state to ratify on June 10, 1919, and Tennessee was the 36th state on August 18, 1920, with a very closely contested state Representative vote of 50 yes to 49 no. The 19th Amendment was officially adopted on August 26, 1920.
However, women’s suffrage in Colorado actually began 27 years before the adoption of the 19th Amendment, in 1893. That year, the state held the Colorado Equal Suffrage Referendum, where the measure passed with 55 percent of the vote. 35,798 Colorado voters cast ballots in favor of the referendum, while 29,551 opposed the measure. The highest support for the referendum came in Mesa county, where 78% of voters approved it, and the lowest support was in Costilla county, where only 16% of the voters approved it.