Sixteen Mile Creek (also known as Sixteenmile Creek), a tributary of the Missouri River, is 69 miles (111 km) long, in western Montana in the United States. If forms at the confluence of the Middle and South forks of Sixteen Mile Creek approximately 6 miles (9.7 km) east of Maudlow. The canyon through which it travels is known as "Sixteen Mile Canyon." The abandoned grade of the Chicago, Milwaukee, St.