Marbury is an unincorporated community in Charles County, Maryland. It has been designated the zip code of 20658. It is 6.3 miles from Indian Head on Maryland Route 224. Smallwood State Park, named for William Smallwood, is located in nearby Rison, Maryland. Smallwood's Retreat, Sweden Point Marina, and an art gallery are located in the park. Smallwood State Park has hosted numerous fishing tournaments, including events in the Bass Anglers Sportsman Society's Bassmasters series.