which states does the mississippi river pass through?
Mississippi Wisconsin Minnesota Kentucky Illinois Tennessee Arkansas Missouri Iowa Louisiana
entailment
 The river roughly defined the American frontier in the 19th century , particularly downstream from Kansas City , where it takes a sharp eastern turn into the heart of the state of Missouri . The major trails for the opening of the American West all have their starting points on the river , including the California , Mormon , Oregon , and Santa Fe trails . The first westward leg of the Pony Express was a ferry across the Missouri at St. Joseph , Missouri . Similarly , most emigrants arrived at the eastern terminus of the First Transcontinental Railroad via a ferry ride across the Missouri between Council Bluffs , Iowa and Omaha . The Hannibal Bridge became the first bridge to cross the Missouri River in 1869 , and its location was a major reason why Kansas City became the largest city on the river upstream from its mouth at St. Louis . 

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 Since the beginning of the 20th century , the Missouri River has been extensively engineered for water transport purposes , and about 32 percent of the river now flows through artificially straightened channels . In 1912 , the USACE was authorized to maintain the Missouri to a depth of six feet ( 1 @.@ 8 m ) from the Port of Kansas City to the mouth , a distance of 368 miles ( 592 km ) . This was accomplished by constructing levees and wing dams to direct the river 's flow into a straight , narrow channel and prevent sedimentation . In 1925 , the USACE began a project to widen the river 's navigation channel to 200 feet ( 61 m ) ; two years later , they began dredging a deep @-@ water channel from Kansas City to Sioux City . These modifications have reduced the river 's length from some 2 @,@ 540 miles ( 4 @,@ 090 km ) in the late 19th century to 2 @,@ 341 miles ( 3 @,@ 767 km ) in the present day . 

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 In 1945 , the USACE began the Missouri River Bank Stabilization and Navigation Project , which would permanently increase the river 's navigation channel to a width of 300 feet ( 91 m ) and a depth of nine feet ( 2 @.@ 7 m ) . During work that continues to this day , the 735 @-@ mile ( 1 @,@ 183 km ) navigation channel from Sioux City to St. Louis has been controlled by building rock dikes to direct the river 's flow and scour out sediments , sealing and cutting off meanders and side channels , and dredging the riverbed . However , the Missouri has often resisted the efforts of the USACE to control its depth . In 2006 , several U.S. Coast Guard boats ran aground in the Missouri River because the navigation channel had been severely silted . The USACE was blamed for failing to maintain the channel to the minimum depth . 

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 The Missouri River is the longest river in North America . Rising in the Rocky Mountains of western Montana , the Missouri flows east and south for 2 @,@ 341 miles ( 3 @,@ 767 km ) before entering the Mississippi River north of St. Louis , Missouri . The river takes drainage from a sparsely populated , semi @-@ arid watershed of more than half a million square miles ( 1 @,@ 300 @,@ 000 km2 ) , which includes parts of ten U.S. states and two Canadian provinces . When combined with the lower Mississippi River , it forms the world 's fourth longest river system . 

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 The water boundaries are still set to be the original thalweg of the rivers . Since then , several have been inundated by lakes created by dams , including the Apalachicola / Chattahoochee / Flint point now under Lake Seminole . 
