The Platte River near its confluence with the Missouri River at Farley, Missouri
The Platte River is a tributary of the Missouri River, about 200 miles (320 km) long,[4] in southwestern Iowa and northwestern Missouri in the United States. It is sometimes known as the Little Platte River to distinguish it from the larger Platte River, also a tributary of the Missouri, in nearby Nebraska; the Platte River of Missouri itself has a tributary known as the "Little Platte River".[5][6][7]
Near its headwaters in Iowa the Platte collects minor branches known as the West Platte River,[10]Middle Platte River,[11] and East Platte River.[12][8]
In Buchanan County, Missouri, it collects the One Hundred and Two River and the Third Fork,[13] which rises in Gentry County and flows southwardly through DeKalb County, past Union Star. The Third Fork collects the Little Third Fork,[14] which flows southwardly through DeKalb and Buchanan Counties, past Clarksdale. Before leaving Buchanan County Castile Creek enters from the northeast.[9]
When Missouri entered the union in 1821, the western border of Missouri from Arkansas to Iowa was based on the confluence of the Kansas River and Missouri River in the West Bottoms in Kansas City. Land in what is now the northwest Missouri was deeded to the Ioway, Sac and Fox tribes.
However, settlers (most notably Joseph Robidoux in St. Joseph, Missouri) began encroaching on the land. Further settlers in northern Missouri were upset about being cut off from the Missouri.
Excerpt from the Lewis and Clark map of 1814 shows the river identified as the "Little River Platte"
In 1836, William Clark (of Lewis and Clark) persuaded the tribes to sell their lands in northwest Missouri. The deal known as the Platte Purchase was named for the river was ratified in 1837 and the tribes were paid $7,500 for an area about the combined size of Delaware and Rhode Island. The land was then annexed to Missouri.
In 1838 settlers used the river (and the Nodaway River) to reach the heart of the newly available land. The Platte River is not used for transportation in modern times although Missouri River steam boats did call on Tracy, Missouri.
Average flow at mile 25.1 is 1,925 cubic feet second (54.5 m3/s). The highest flow was 37,800 ft3/s (1070 m3/s) during the Great Flood of 1993 on July 26, 1993. The lowest flow was 12 ft3/s (0.33 m/s) during a drought in August 1989.
