Areas

Northwest Branch
Located near Silver Spring, this are has been around for a long time but has just recently in the past two years been fully developed. Most of the best lines have already been climbed, however there are still a few boulders left undone. This is probably the best place to go for hard bouldering in maryland.
The classics of this area include Gillians Feat (V0), Ride the Lightning (V3), Pathway to the Stars (V2), Right hand of Thor (V4), Doom (V5), River Dyno (V6), Pimpas Paradise (V8), Chaos Roof (V9), and Curtain Call (V10)

Rocky Gorge Reservoir
Really small area with maybe 50 problems in total, also near Silver Spring.
The clasics of this area are Halloween Americana (V1), Red Summer Sun (V3), Deeper Than Bones (V5), Crystal Baller (V7), The Missing Link (V8), and Mordor (V10).

Carderock
Although mainly a toproping crag, there is also plenty of bouldering to be done here.
The classics incude Bucket of Blood arete (V5), Buckets of Blood (V9).

Great Falls
Again this is mainly a toproping crag but there is definately a good number of hard, classic boulders. There is also potential for further deveopment to be done here.
The classics of this area include Arete Line (V4), Unnamed (V5), Double Slap (V9), Unnamed (V9), and The Diary of a Madman (V13? project)

Alberton Road
This is a small area with few problems, but it is so close to Baltimore City that it's worth checking out. For those of you with GPS the parking lot is at 39.3154,-76.793329 You can also enter that into google maps and get directions. Walk down the nice paved trail and the boulders will be on your right, only about 100 yards in. I never bothered naming the enormous roof, so I just left it as "Project Roof". Direct starts to both Frameshift and Project roof would be worthy. On the other side of the river is a boulder along side the train tracks with the name "Roger" in white graffiti on it. It looks hard and of good quality, but to my knowledge has never been tried.
Area classics include: Frameshift (V5+), Project Roof (V6), Highball (V3), Roger Wall (project)