The Jessie Scouts were irregular soldiers during the American Civil War on the side of the Union who frequently operated in the territory of the Confederate States of America.
The unit was created by John C. Frémont and named in honor of his wife, rather than of a Colonel Jessie, who was himself a myth. 
 Bakeless, p. 212.
Bakeless, John (1997). Spies of the Confederacy. Courier Dover Publications. ISBN 0-486-29865-5.