Sarah Emma Edmonds (December 1841 - September 5, 1898), was an American woman who served as a transracial and cross-dressing spy for the Union in the American Civil War. She was born in New Brunswick, Canada, but moved to the United States in 1856. During the war, she enlisted, disguised as a man named Frank Thompson, and served as a male nurse, participating in several campaigns, including the Battle of First Bull Run. As Frank Thompson, she also served as a spy, occassionally disguising herself as an African American or a woman, or sometimes both. At one point, she disguised herself as an Irish peddler with the name of Bridget O'Shea.
Edmonds career as Frank Thompson came to an end when she contracted malaria. Unable to go to the military hospital, because she would be revealed as a woman, she left the army and checked herself in to a private hospital, intending to return to military life once she had recuperated. Once she was better, however, she saw posters looking for Frank Thompson as a deserter. Rather than return to the army as a woman, she decided to serve as a female nurse.
She published Nurse and Spy in the Union Army after the war. In 1867, she married L. H. Seelye, a Canadian mechanic with whom she had three children. In 1886 she received a government pension rewarding her military service. Edmonds died in La Porte, Texas, and is buried in Washington Cemetery, in Houston, Texas.