| Smallwood State Park | |
| Map: | USA Maryland |
| Map Size: | 280 |
| Relief: | 1 |
| Location: | Charles County, Maryland, United States |
| Nearest Town: | Marbury, Maryland |
| Coordinates: | 38.5564°N -77.1853°W |
| Area Acre: | 984 |
| Elevation: | 3feet |
| Designation: | Maryland state park |
| Established: | 1958 |
| Website: | Smallwood State Park |
Smallwood State Park is a public recreation and historic preservation area located on Mattawoman Creek near Marbury, Charles County, Maryland. The state park preserves Smallwood's Retreat, the plantation home of former Continental Army officer and Governor of Maryland, Major General William Smallwood. The park's include a marina, boat ramps, picnicking facilities, campsites, cabins, trails, and nature center.
After a succession of occupants left Smallwood's Retreat in ruins, a local citizens group organized in 1934 to see to its protection. Restoration took place between 1954 and the dedication of the original thirty-acre state park in 1958.