The main column is the the north two-thirds of the Sentinel, and the smaller portion is the south side of the tower. This smaller column, when viewed from the top, is split by a vertical crack which leaves the rock mass on the river side a large detached boulder resting on the top of the smaller column. This rock mass will move slightly if enough pressure is placed on it. One would be wise, in view of this instability, to always belay from the bolts drilled into the top of the north column of the Sentinel. Starting from the Quadrangle, climb anywhere on the east face of the larger column of the Sentinel.
Holds are abundant.
The route is long enough and exposed enough to be an exciting first climb or first lead. Near the right edge of the west face of the Sentinel, at its base, is a foul-looking overhanging crack. Use bruising hand jams for 30 feet to the ledge, where the route ends. Do not expect to get any help from face holds. Don't use the north-south crack in the top of the smaller column to set belay anchors.