 <unk> in the watershed vary widely , ranging from just over 400 feet ( 120 m ) at the Missouri 's mouth to the 14 @,@ 293 @-@ foot ( 4 @,@ 357 m ) summit of Mount Lincoln in central Colorado . The river itself drops a total of 8 @,@ <unk> feet ( 2 @,@ <unk> m ) 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 500 feet ( 150 m ) at the eastern border of the watershed , but is over 3 @,@ 000 feet ( 910 m ) above sea level in many places at the base of the Rockies . 
