Seneca Falls Convention in the context of Rochester Women's Rights Convention of 1848

The Nineteenth Amendment (Amendment XIX) to the United States Constitution prohibits the United States and its states from denying the right to vote to citizens of the United States on the basis of sex, in effect recognizing the right of women to vote. The amendment was the culmination of a decades-long movement for women's suffrage in the United States, at both the state and national levels, and was part of the worldwide movement towards women's suffrage and part of the wider women's rights movement. The first women's suffrage amendment was introduced in Congress in 1878. However, a suffrage amendment did not pass the House of Representatives until May 21, 1919, which was quickly followed by the Senate, on June 4, 1919. It was then submitted to the states for ratification, achieving the requisite 36 ratifications to secure adoption, and thereby went into effect, on August 18, 1920. The Nineteenth Amendment's adoption was certified on August 26, 1920.

Before 1776, women had a vote in several of the colonies in what would become the United States, but by 1807 every state constitution had denied women even limited suffrage. Organizations supporting women's rights became more active in the mid-19th century and, in 1848, the Seneca Falls convention adopted the Declaration of Sentiments, which called for equality between the sexes and included a resolution urging women to secure the vote. Pro-suffrage organizations used a variety of tactics including legal arguments that relied on existing amendments. After those arguments were struck down by the U.S. Supreme Court, suffrage organizations, with activists like Susan B. Anthony and Elizabeth Cady Stanton, called for a new constitutional amendment guaranteeing women the same right to vote possessed by men.

Women's suffrage, or the right of women to vote, was established in the United States over the course of the late 19th and early 20th centuries, first in various states and localities, then nationally in 1920 with the ratification of the 19th Amendment to the United States Constitution.

The demand for women's suffrage began to gather strength in the 1840s, emerging from the broader movement for women's rights. In 1848, the Seneca Falls Convention, the first women's rights convention, passed a resolution in favor of women's suffrage despite opposition from some of its organizers, who believed the idea was too extreme. By the time of the first National Women's Rights Convention in 1850, however, suffrage was becoming an increasingly important aspect of the movement's activities.

The Declaration of Sentiments, also known as the Declaration of Rights and Sentiments, is a document signed in 1848 by 68 women and 32 men—100 out of some 300 attendees at the first women's rights convention to be organized by women. Held in Seneca Falls, New York, the convention is now known as the Seneca Falls Convention. The principal author of the Declaration was Elizabeth Cady Stanton, who modeled it upon the United States Declaration of Independence. She was a key organizer of the convention along with Lucretia Coffin Mott, and Martha Coffin Wright.

According to the North Star, published by Frederick Douglass, whose attendance at the convention and support of the Declaration helped pass the resolutions put forward, the document was the "grand movement for attaining the civil, social, political, and religious rights of women."

Elizabeth Cady Stanton (née Cady; November 12, 1815 – October 26, 1902) was an American writer and activist who was a leader of the women's rights movement in the U.S. during the mid- to late-19th century. She was the main force behind the 1848 Seneca Falls Convention, the first convention to be called for the sole purpose of discussing women's rights, and was the primary author of its Declaration of Sentiments. Her demand for women's right to vote generated a controversy at the convention but quickly became a central tenet of the women's movement. She was also active in other social reform activities, especially abolitionism.

In 1851, she met Susan B. Anthony and formed a decades-long partnership that was crucial to the development of the women's rights movement. During the American Civil War, they established the Women's Loyal National League to campaign for the abolition of slavery, and they led it in the largest petition drive in U.S. history up to that time. They started a newspaper called The Revolution in 1868 to work for women's rights.