Carderock 

Carderock's a busy, busy place. On any given weekend, you can find local gyms and schools using this area for groups and classes, scouts climbing up and down, and dozens of locals out with their buddies or solo. No solitude here.

Top-roping is the recommended technique. There are no bolts worth trusting, and everything is so slick from use it's hard to get gear to stick.

The secret of Carderock climbing is out! Once known only by locals, the area now draws climbers from as far away as Virginia and has even been visited by a climber from California: www.npr.org/templates/story/story.php?storyId=15825820

As far away as VA...? just across the river? hell of a trek!

Carderock is a huge sandbag. This is quite evident from the video that Dan posted which shows a 5.15 climber falling multiple times on a climb rated "only" 12d. On TR, no less. (That's a great little video, BTW.)

Here is a bunch of additional information from about.com Climbing:
climbing.about.com/od/wheretoclimb/fr/Carderock-Rock-Climbin>>>

Carderock, located along the east side of the Potomac River in Maryland just north of Washington DC, is one of the most popular urban climbing areas in the eastern United States. The 25- to 60-foot-high, west-facing cliff offers lots of easy and moderate top-rope routes, with a few harder climbs as well as numerous eliminate routes and boulder problems.

Most Popular Cliff on East Coast
Since Carderock is in the Washington DC metroplex, a densely populated area that also includes cities in Maryland and Virginia, it’s extremely popular—probably the most climbed cliff in the eastern United States. Local climbers come after work for a few quick routes, while large groups, including guided trips, Boy Scout troops, and others, flock on the weekends. To avoid the crowds, plan on climbing during the week when it’s usually quiet and you can put a top-rope on any climb you want.

Geology: Carderock Schist is Slick
Carderock climbing ranges from easy to hard and often depends on the temperature and humidity. Summer is not the best time to climb the crag’s harder routes. The rock surface is often slick and polished, making careful footwork important. Some climbs also feature quartz crystal knobs and nubbins, allowing for friendly moves on solid handholds. The occasional crack climbs found at Carderock offer laybacks and jams. The cliff at Carderock is composed of mica schist, a metamorphic rock that was originally deposited as shale and mudstone and was later subjected to intense heat and pressure which transformed or metamorphosed the original deposit.

Solid Rock for Solid Climbing
The rock at Carderock is generally sound with a clean surface although sometimes hollow flakes or loose holds are found. Most routes, however, have been climbed a lot so any loose rock has been cleaned off. The cracks, however, are not ideal for leading since protection is often difficult to place and the schist has a reputation for being friable and breakable if a piece of gear is subjected to a leader fall.

One of Oldest Climbing Areas in Eastern USA
Carderock offers lots of fun easy and moderate climbs that are easily top-roped from a rope strung from tree anchors.

Carderock, with its proximity to Washington DC, is one of the oldest established climbing areas in the eastern United States. Gustave Gambs, partnered with Don Hubbard and Paul Bradt, introduced climbing here in the 1920s. These early climbers used laid manila ropes, which were looped around their waists and cinched up with a bowline knot. They either top-roped routes or led them, pounding pitons in cracks for protection.

Early Carderock Climbing
In the 1940s, climbers continued to explore Carderock and Great Falls, particularly in Mather Gorge on the Virginia side of the Potomac River farther upstream. Carderock, however, was more easily accessible to city climbers. The area’s first climbing guide, “Rock Climbs Near Washington” written by Don Hubbard, was published in the Potomac Appalachian Trail Club (PATC) Bulletin in July, 1943.

Herb and Jan Conn Go Climbing
In 1942, Herb and Jan Conn, who later settled in the Black Hills of South Dakota and opened many routes at The Needles as well as explored and mapped Wind Cave and Jewel Cave, began climbing at Carderock. The Conns climbed and named lots of the routes at Carderock, including Herbie’s Horror in 1942. This route, first climbed by Herb Conn, was one of the first 5.9 routes in the eastern United States. Other Conn routes were a bunch of top-ropes on Jan’s Face and Ronnie’s Leap, which Jan Conn says “was named for our dog, who mistook that spot for the walk down near the Spider Walk. He came hurdling down while we watched in dismay, but at the bottom he trotted off without a backward glance.”

Letter from Jan Conn

In 2008, Vincent Penoso with the PATC sent a copy of their new guidebook to Herb and Jan Conn. Jan replied with a thank you letter, which is scanned and posted on the PATC website. She wrote: “We had a ball reading your new guide to the climbing at Carderock. We marvel at the places people now climb. The last time we were there (1985) the glaze made by slipping feet below the Spider’s Walk hand crack brought to our minds that these climbs get harder as the years past. We’re glad we did all our climbing before the polishing. The guide brought back fond memories of the period in our lives when we realized that life is what you want it to be. If climbing is more important than having a prestigious job or a family, go for it!” Well said, Jan!

Carderock Climbing Equipment
Carderock is a top-rope climbing area although some routes can be led. All top-rope anchors are trees either along the cliff-top or set back. Bring an extra rope or length of rope, preferably static, to create an equalized top-rope anchor using trees and to extend the anchor to a master point over the cliff edge. Long lengths of webbing can also be used for anchors. Also bring several slings and locking carabiners. A small assortment of Stoppers and cams can supplement your anchor too. While the top edge of the cliff isn’t sharp, you can also bring a sheath, a section of garden hose works fine, to protect the fixed rope where it drapes over the cliff-top. Read Top-Rope Climbing Equipment for more gear information.

Location
North of Washington DC and the I-95 beltway along the Potomac River in Maryland.

Finding Carderock
Carderock is on the Maryland side of the Potomac River about 12 miles north of Washington DC. Follow I-495, the Capitol Beltway, and take Exit 13. Drive north on the Clara Barton Parkway to the first exit for Carderock Recreation Area and the Naval Surface Warfare Center Carderock Division. Turn left and drive across the parkway on a bridge into the national parkland. Follow the road to the last parking area. A trail starts on the south side of restrooms. Follow it for 0.1 mile to the cliff-top. Access the cliff base by scrambling down a gully in the middle of the cliff or by hiking right and descending around the north edge of the cliff.

Take the Bus to Carderock
If you’re visiting and don’t have a car, you can reach Carderock from Washington DC. Take bus #32 from the Bethesda Bus Station in Washington DC. Ask the drive to drop you off at the gate for the naval base. Cross the bridge over the parkway and hike up to the road to the parking area and trailhead. The bus ride takes about 30 minutes.