The reservoir was created in 1914 by damming the Gunpowder River. The lake is one of three reservoirs created for Baltimore City's water supply. The lake and the river are surrounded by a wooded area to provide a buffer zone that protects the water supply from pollution and sedimentation. The buffer zone also provides wildlife habitat and recreation areas, with hiking trails, picnic areas, fishing, hunting, and birdwatching.
The reservoir has many hiking trails around it.
I have spent most of my time here in the areas around Morgan Mill Road and Loch Raven Drive. This area is considerably more crowded today than it was when I lived in the area and spent a good deal of time exploring here. As a kid I often just hiked through the woods, following the shore line you could hike a mile or more before reaching the end of the reservoir property. On weekends a three mile stretch of Loch Raven Drive is closed to cars, but open to bikes and foot traffic, starting at Morgan Mill Road. There are hiking trails through the woods where you can hike or birdwatch. Parking can be difficult, so you might plan on getting there early in the morning to find a parking spot.
A reader named Ed e-mailed some tips for visitors to Lock Raven. Ed tells us there is parking at the Paper Mill Road bridge, with some good hiking and wildlife watching as you hike towards the reservoir (south) from the bridge. Blue Herons, Scarlet Tanagers, Bluebirds, and Beaver are some of the wildlife he has seen there.