Chief Mountain (Blackfoot: Ninaistako) (9,085 feet (2,769 m)) is located in the U.S. state of Montana on the eastern border of Glacier National Park and the Blackfeet Indian Reservation.[4][5] The mountain is one of the most prominent peaks and rock formations along the Rocky Mountain Front, a 200 mi (320 km) long overthrust fault, known as the Lewis Overthrust, which extends from central Montana into southern Alberta, Canada.