It was not until five years after we first went to press that women achieved the right to vote across the United States. In 1915, only eight states allowed women to vote; one of them, Montana, elected Jeannette Rankin to the U.S. House of Representatives in 1916, making her the first woman to serve in Congress. The 19th Amendment was ratified in 1920, finally guaranteeing that a U.S. citizen could not be denied the right to vote based on their sex.