The 19th Amendment to the U.S. Constitution granted women the right to vote. It was passed by Congress on June 4, 1919, and ratified on August 18, 1920. This amendment legally guaranteed American women the right to vote, but it took decades of agitation and protest to achieve this milestone. The campaign for woman suffrage began in the mid-19th century, and several generations of woman suffrage supporters lectured, wrote, marched, lobbied, and practiced civil disobedience to achieve what many Americans considered a radical change of the Constitution. Between 1878, when the amendment was first introduced in Congress, and August 18, 1920, when it was ratified, champions of voting rights for women worked tirelessly, but strategies for achieving their goal varied. Some pursued a strategy of passing suffrage acts in each state, while others worked towards a constitutional amendment. By 1916, almost all of the major suffrage organizations were united behind the goal of a constitutional amendment. When New York adopted woman suffrage in 1917 and President Wilson changed his position to support an amendment in 1918, the political balance began to shift.

It is worth noting that prior to the passage of the 19th Amendment, women had the right to vote in various elections in a number of states and localities. For example, New Jersey recognized womens right to vote in 1797, but women were stripped of their voting rights in 1807 when the state passed a law allowing only free white males the right to vote. In 1869, Wyoming territory granted women the right to vote motivated less by gender equality and in large part by the hope that the law would attract women to the territory which had a 6:1 men to women ratio. The territories of Utah, Washington, and Montana were among the first and passed womens voting rights during the 1870s and 1880s.

It is also important to note that while the 19th Amendment secured all women the right to vote, in practice, many women of color were excluded. Black women, Native American women, Asian American women, and women from other racial and ethnic minority groups were discriminated against for 45 more years until the passage of The Voting Rights Act of 1965 (VRA) .