Elevations in the watershed vary widely, ranging from just over at the Missouri's mouth to the summit of Mount Lincoln in central Colorado. The river drops from Brower's Spring, the farthest source. Although the plains of the watershed have extremely little local vertical relief, the land rises about 10 feet per mile (1.9 m/km) from east to west. The elevation is less than at the eastern border of the watershed, but is over above sea level in many places at the base of the Rockies.