Know Before You Go
From the Capital Beltway (I-495), take the Georgia Avenue Southbound exit; turn left on Seminary Road. Seminary Road bears off to the right at a traffic light, but continue through the traffic light onto Linden Lane. After about a mile, Linden Lane intersects with Cassedy Street; the best way to continue is to park on Linden Lane and proceed onto Cassedy on foot.
Once a month, the Save Our Seminary group gives guided tours of the grounds and inside a couple of the buildings; check their website for times.
As of summer 2017, most of the former campus has been converted into townhouses, and the best way to access the remaining ruins is via Smith Street, a dead end that sweeps around toward the castle, a former dormitory, and a handful of statues that are surrounded by overgrowth. Entering via Smith Street and driving to the end allows access to the remaining ruins on foot, without having to walk through the considerable undergrowth that prevents access from the Linden Place side. Be aware that the remaining grounds have been purchased by a development company and plans are in place for renovations, but so far the remaining structures remain untouched.