Tower Rock State Park, Rock formation state park in Cascade County, Montana, US.

Tower Rock is a stone formation that rises 424 feet (129 m) above the Missouri River Canyon, marking the entrance to the Adel Mountains Volcanic Field. The structure consists of volcanic rock built atop older sedimentary layers.

Tower Rock is a shonkinite intrusion in the Adel Mountains Volcanic Field, about 75 million years old; as softer surrounding rock eroded, the harder shonkinite was left standing. On July 16, 1805, Meriwether Lewis, with Jean Baptiste Lepage and John Potts, became the first non-Native to see it and named it "the tower" in his journal. The 87.2 acres around the rock were listed on the National Register of Historic Places on March 18, 2002, and the 140-acre state park was created in 2004.

The Piegan Blackfeet considered Tower Rock sacred and held ceremonies there; individuals also came alone to pray and meditate. The Bitterroot Salish and Lower Kootenay passed by on their way through the Adel Mountains to hunting grounds, and wickiup frames were built in the area and reused as people moved between summer hunts and winter camps.

A maintained trail goes about a quarter mile (400 m) to the saddle base with five informational signs along the way. The path is easy to walk and gives good views of the surrounding landscape.

Tower Rock is a shonkinite intrusion: as the softer surrounding rock eroded away, this harder igneous rock was left standing. Its south outcrop rises 161 feet (49 m) above the north one, and the flat ground around its base holds old channels of the Missouri River.