The first woman to vote in a U.S. federal election was Jeannette Rankin, who cast her ballot in the special election for Congress in Montana in 1916. However, the significant milestone in women's suffrage came with the ratification of the 19th Amendment in 1920, granting women the right to vote across the nation. This achievement was the result of decades of activism and struggle by suffragists, who campaigned for equal voting rights, often facing significant opposition and societal backlash. The 19th Amendment marked a crucial step toward gender equality and empowered women to participate fully in the democratic process.