This is a nice, little area in Lawrence, which is nearly to the New Hampshire line (I thought it was in Andover), with short routes of low end difficulty. The park is 80 acres and belongs to the city. The rock is fairly rough with buckets galore. Consider long slings and a sturdy rope for climbing here. Anchors require pro. Some will just boulder here. Something was written about supposedly rock to 100 feet here. Addendum: I never found anything bigger than 30 feet.
The crags from North to South are First Impressions, Desperado, Inner Walls, Building Blocks, Petroleum Based Buttress, FK Face, City Dump, City Park, Remnants. Above City Park is a small boulder.
Apparently, below The Buidling Blocks area is a new bouldering area.
To get there from Boston, go North on I-93, go East on I-495 to exit 42A. Go South on Hwy 114 for 0.4 mi. Paaark on the West side. Go South away from the North Andover shopping mall. Take a left (East) and follow a dirt road. The first crag you will reach is First Impressions.
Mountain Project's determination of some of the classic, most popular, highest rated routes for Denrock:
This unfortunately named climb ascends the zig-zagging hand crack on the north side of the Petroleum Based Buttress. Start on thin face moves to gain the crack. A few strenuous jam and layback moves are required to gain a ledge. From here, cop out up a dirty crack to the left, or continue up the unprotected but easy arete to the anchors....[more]Browse More Classics in MA
Don't climb at Denrock much, but when I went last I saw nothing even close to 100ft. Highball bouldering or short short top-rope. Many TR anchors are being bolted. Kinda dirty (in a ghetto way) and super contrived much like Lincoln Woods though the rock is different. Maybe enough for a weekend if you climb hard (past V8 or so) but if your like me you'll find some projects, especially with variants. Not destination worthy but if your in the area or passing through on the way to P-tuck or Lincoln worth checking out.
New to mtn prjct, maybe next time I'm down that way I'll take some photos.
No face at Den Rock exceeds 30 feet, Desperado being the highest. Most of the crags are around 20-25. The rock is pegmatite, a sharp granite with lots of crystals. In 2007 a large number of glue-in anchors were installed, protecting most routes on the six main crags. This makes TRing much easier, as there is little natural pro at the top and very few trees. The bouldering referred to in the description is spread out but of good quality. Below the Building Blocks face are two boulders, each with several moderate lowball problems. The Remnants and City Dump areas are short enough (12-15 and 15-20 feet respectively) to be bouldered. City Dump especially is known as a fine training boulder, as it overhangs and is covered with good crimps and edges. Many eliminates can be made here, allegedly ranging in difficulty up to V9. Above the City Park section is an 8-10 foot slabby boulder with short moderate problems.