Montanas Crazy mountains rise between what two rivers?

Spanning a distance of 40 miles (64 km), the Crazy Mountains are located between the Musselshell and Yellowstone rivers. The highest peak is Crazy Peak at 11,209 feet (3417 m). Rising over 6,000 feet (1,830 m) above the Great plains to the east, the Crazies dominate their surroundings and are plainly visible just north of Interstate 90.