Turtleback Mountain is a 2,203-foot peak in New Hampshire’s Ossipee Mountains that rises above Bald Knob. Its summit is especially notable for columnar jointing, a distinctive rock formation that gives the mountain particular geological interest. The top once held an observation tower, reflecting its past use as a lookout as well as a destination for hikers. Today it is recognized as one of the peaks of the Ossipee range and as a natural viewpoint defined by its height and exposed stone summit.