Which U.S. constitutional amendment established women's suffrage nationwide in 1920?

The Nineteenth Amendment established women's suffrage nationwide in 1920.

It prohibited the United States and its states from denying the right to vote on the basis of sex. Congress passed the amendment in 1919, and Tennessee supplied the decisive thirty-sixth state ratification on August 18, 1920.

The amendment was the culmination of decades of organizing by the women's suffrage movement. Activists including Susan B. Anthony, Elizabeth Cady Stanton, Ida B. Wells, and Carrie Chapman Catt used petitions, marches, speeches, and legal campaigns to press for voting rights.

The amendment did not immediately guarantee equal access to the ballot for every woman. Many women of color still faced discriminatory state laws, intimidation, and administrative barriers, especially in the Jim Crow South. Later civil-rights legislation addressed some of those obstacles.