The local rock formations are some of the most distinctive in the state of Oklahoma. Just north of Broken Bow, sedimentary rock has been thrust upward due to an ancient collision of the North American and South American Plates, forming what is now the Ouachita Mountains. Evidence of what is called the Ouachita orogeny can be seen all over the park, where some layers of rock can be seen tilted up at angles of about sixty-degrees. These geologic features can be easily viewed around Broken Bow Lake and Mountain Fork River, where erosion has left much of the rock exposed. The unique geology of the area inspires frequent field trips by geology students from numerous colleges and universities.