The 7,380-acre Prettyboy Reservoir CWMA is owned by the City of Baltimore and is managed to protect the reservoir. The area is open to hiking, rowing or paddle boating, bird watching, horseback riding and nature photography year-round, and for archery hunting during a regulated season. The reservoir is also managed for warm, cool, and cold water fish species and offers fishing opportunities. Prettyboy Reservoir is located primarily in northwestern Baltimore County with a small portion extending into northeastern Carroll County.

The water from Prettyboy Reservoir is transferred to Loch Raven Reservoir via Gunpowder Falls rather than directly to Baltimore. It is then transferred via tunnel from Loch Raven to the Montebello Filtration Plants in Baltimore for treatment and distribution. Prettyboy Dam, completed in 1932, impounds the Gunpowder Falls to create the Reservoir.