The influential leader of the suffragette movement in the United States was Elizabeth Cady Stanton. A prominent social activist, she played a crucial role in advocating for women's rights, including the right to vote. Stanton co-organized the historic Seneca Falls Convention in 1848, where she presented the Declaration of Sentiments, demanding equal rights for women. Her tireless efforts and eloquent writings helped shape the feminist movement, making her an essential figure in the struggle for gender equality in America.