Leavenworth may refer to some places in the United States:
- Leavenworth County, Kansas, a county in northeast Kansas
- Leavenworth, Kansas, a city in the county which includes the fort and federal prisons within its city limits
- Fort Leavenworth, a U.S. Army base that is home to the Fort Leavenworth National Cemetery, United States Army Command and General Staff College and United States Army Combined Arms Center
- United States Penitentiary, Leavenworth, a civilian medium security prison built on the grounds of Fort Leavenworth
- United States Disciplinary Barracks, a military maximum security prison built on the grounds of Fort Leavenworth
- Leavenworth, Kansas, a city in the county which includes the fort and federal prisons within its city limits
- Leavenworth, Indiana
- Leavenworth, Washington
- People
- Henry Leavenworth, U.S. soldier who established Fort Leavenworth
- Jesse Henry Leavenworth, U.S. soldier, son of Henry Leavenworth