like El Capitan in Yosemite, the defining feature of Cannon Mountain is really not so much a peak but a wall - the Cannon Cliff. The Cannon Cliff (the site of the famous profile called the Old Man of the Mountain, visible from across Franconia Notch) - a full thousand feet in height and about a mile long - is the largest vertical face in the Northeast and a classic destination for alpine climbing, both in winter and summer. In the summer the wall abounds with alpine rock routes of fantastic quality, ranging from moderate free routes like Lakeview (5.5) and Whitney-Gilman Ridge (5.7) to hard aid. There are also classic hard free climbs such as the VMC direct (5.11). Some of the aid lines are long and difficult enough to require a bivy, making Cannon the only Big Wall in the northeast.
The nature of the climbing at Cannon is different than other New England locations. Because on average the level of the Cannon climbers is higher than most, the grades tend to reflect this - in other words, some people will say they are sandbagged. For instance, it is unclear how the finish to Lakeview ever got the rating of 5.5, considering it is considerably harder than many 5.7 routes at Cathedral Ledge.
In addition, many of the routes are much less well defined than in other areas, with many variations possible and good routefinding skills are required. These things, plus the length of the routes and the risk of rockfall make Cannon climbing a more serious undertaking than other routes of comparable grade in New England, which to many adds to its attraction.
In the winter, Cannon becomes even more serious. The "easiest" and most frequently climbed winter route is the great Black Dike - traditionally rated at WI5-. While certainly not easy and of a serious alpine nature, the Dike is at least well established, follows a line that you can't miss, and usually has some reliable fixed gear that allows fairly straightforward rappels if neccesary. This is the case only with the Dike. Other winter routes on Cannon (including the Dike's neighbor Fafnir) are considerably more involving and usually much harder in the technical sense as well, often featuring thin, hard to protect ice or sections with no ice at all. Some are mixed routes; some involve substantial aid climbing; all are serious undertakings!
In addition, Franconia Notch (the narrow glacier-cut valley which Cannon faces) is known for the crappiness of its weather. It is often bad even when it's good elsewhere, and if it's bad elsewhere than it's downright horrendous in the Notch. This must also be considered when climbing on Cannon, both in winter and in summer.
Cannon is located on the west side of Franconia Notch, along route 93 about 10 miles north of the town of Lincoln, NH. There are two parking lots: a large one at Profile Lake, and a smaller one at Boise Rock which is about a mile to the south and directly across the Black Dike. The Profile Lake lot involves making a U turn if you are coming from the south - you have to do this at the Cannon tramway exit. If you park at the Boise Rock lot you don't need to turn around, but you must then cross the highway to get to the approach.
To actually get to the wall there is a trail running along the entire base; access trails to individual routes branch off from it One goes up on the north end approaching the Lakeview route, another in the center to the Main Face, and another to the Black Dike/Whitney-Gilman area near the south end. The base of the wall is a talus slope and caution should be excercised; in the winter, parts of the slope can be avalanche prone after very heavy snowfalls.
There is a sing-in box at Profile Lake; it is highly reccomended that all climbers sign both in and out (MAKE SURE you sign out after you're done if you singed in, or people will go out and start looking for you!!) If you parked at Boise Rock it is still reccomended to walk over to Profile Lake and sing in.
When To Climb
Cannon has been climbed all year; in general some of the rock tends to be wet through the spring (until mid may) due to melting snow and ice above. Most years the big ice routes take some time to form, usually at least until mid December; but the Dike has been done before Halloween (like this season). Early fall can be very good, with beatiful weather and fall foliage, but late fall can have really crappy weather and still no ice. Mid summer is not bad either (except on really hot days you won't have to deal with the heat and humidity that affects most of New England) but watch out for thunderstorms - they can come up unexpectedly from the west as the wall is east facing.
there is a campground (lafayette place) at the base. The wall is in a state park so camping is not allowed (i think), but this does not include bivies to my knowledge. I will have more specific info when i edit the site.