Editing Missouri River (section)

==Course==
From the Rocky Mountains, three streams rise to form the headwaters of the Missouri River:

*The longest source stream begins near [[Brower's Spring]] in southwest [[Montana]], {{convert|9100|ft|m}} above sea level on the southeastern slopes of [[Mount Jefferson (Bitterroot Range)|Mount Jefferson]] in the [[Centennial Mountains]]. From there it flows west then north; runs first in [[Hell Roaring Creek]] then west into the [[Red Rock River (Montana)|Red Rock]]; swings northeast to become the [[Beaverhead River]]; and finally joins with the [[Big Hole River|Big Hole]] to form the [[Jefferson River]].
*The [[Firehole River]], which originates in northwest [[Wyoming]] at [[Yellowstone National Park]]'s Madison Lake, joins with the [[Gibbon River]] to form the [[Madison River]].
*The [[Gallatin River]] flows out of Gallatin Lake which is also in Yellowstone National Park.

[[File:Holter Lake.jpg|thumb|left|alt=View of a deep blue lake surrounded by low mountains|[[Holter Lake]], a reservoir on the upper Missouri River]]
The Missouri River officially starts at the confluence of the Jefferson and Madison in [[Missouri Headwaters State Park]] near [[Three Forks, Montana]], and is joined by the Gallatin a mile (1.6&nbsp;km) downstream. It then passes through [[Canyon Ferry Lake]], a reservoir west of the [[Big Belt Mountains]]. Issuing from the mountains near [[Cascade, Montana|Cascade]], the river flows northeast to the city of [[Great Falls, Montana|Great Falls]], where it drops over the [[Great Falls (Missouri River)|Great Falls of the Missouri]], a series of five substantial waterfalls. It then winds east through a scenic region of canyons and badlands known as the Missouri Breaks, receiving the [[Marias River]] from the west then widening into the [[Fort Peck Lake]] reservoir a few miles above the confluence with the [[Musselshell River]]. Farther on, the river passes through the [[Fort Peck Dam]], and immediately downstream, the [[Milk River (Alberta–Montana)|Milk River]] joins from the north.<ref name="topoquest">{{cite web |publisher = U.S. Geological Survey |title = United States Geological Survey Topographic Maps |website= [[TopoQuest]] |url = http://www.topoquest.com/map.php |access-date = May 8, 2010 |archive-url = https://web.archive.org/web/20120510222118/http://www.topoquest.com/map.php|archive-date = May 10, 2012|url-status = dead}}</ref><ref name="ACMEmapper">{{cite map |website=ACME Mapper |title=USGS Topo Maps for United States |cartography=U.S. Geological Survey |access-date=May 8, 2010 |url-status=live |url=http://mapper.acme.com/ |archive-url=https://web.archive.org/web/20080102075829/http://mapper.acme.com/ |archive-date=January 2, 2008}}</ref>

Flowing eastward through the plains of eastern Montana, the Missouri receives the [[Poplar River (Montana–Saskatchewan)|Poplar River]] from the north before crossing into [[North Dakota]] where the [[Yellowstone River]], its greatest tributary by volume, joins from the southwest. At the confluence, the Yellowstone is actually the larger river.{{efn|
The Missouri's flow at [[Culbertson, Montana]], {{cvt|25|mi|km}} above the confluence of the two rivers, is about {{cvt|9820|cuft/s|m3/s}}<ref>{{cite web |url=http://wdr.water.usgs.gov/wy2010/pdfs/06185500.2010.pdf |title=USGS Gage #06185500 on the Missouri River near Culbertson, MT |publisher=U.S. Geological Survey |website=National Water Information System |date=1941–2010 |access-date=July 4, 2011 |url-status=live |archive-url=https://web.archive.org/web/20111028092212/http://wdr.water.usgs.gov/wy2010/pdfs/06185500.2010.pdf |archive-date=October 28, 2011}}</ref> and the Yellowstone's discharge at [[Sidney, Montana]], roughly the same distance upstream along that river, is about {{cvt|12370|cuft/s|m3/s}}.<ref>{{cite web |url=http://wdr.water.usgs.gov/wy2010/pdfs/06329500.2010.pdf |title=USGS Gage #06329000 on the Yellowstone River near Sidney, MT |publisher=U.S. Geological Survey |website=National Water Information System |date=1911–2010 |access-date=July 4, 2011 |archive-url=https://web.archive.org/web/20111028092834/http://wdr.water.usgs.gov/wy2010/pdfs/06329500.2010.pdf |archive-date=October 28, 2011 |url-status=live}}</ref>
}}
The Missouri then meanders east past [[Williston, North Dakota|Williston]] and into [[Lake Sakakawea]], the reservoir formed by [[Garrison Dam]]. Below the dam the Missouri receives the [[Knife River]] from the west and flows south to [[Bismarck, North Dakota|Bismarck]], the capital of North Dakota, where the [[Heart River (North Dakota)|Heart River]] joins from the west. It slows into the [[Lake Oahe]] reservoir just before the [[Cannonball River]] confluence. While it continues south, eventually reaching [[Oahe Dam]] in [[South Dakota]], the [[Grand River (South Dakota)|Grand]], [[Moreau River (South Dakota)|Moreau]] and [[Cheyenne River]]s all join the Missouri from the west.<ref name=topoquest/><ref name=ACMEmapper/>

The Missouri makes a bend to the southeast as it winds through the Great Plains, receiving the [[Niobrara River]] and many smaller tributaries from the southwest. It then proceeds to form the boundary of South Dakota and [[Nebraska]] and is joined by the [[James River (Dakotas)|James River]] from the north. At [[Sioux City]] the [[Big Sioux River]] comes in from the north, after which the Missouri forms the [[Iowa]]–Nebraska boundary. It flows south to the city of [[Omaha, Nebraska|Omaha]] where it receives its longest tributary, the [[Platte River]], from the west.<ref>{{cite encyclopedia |title={{grey|[no title cited]}} |encyclopedia=Twentieth Century Encyclopædia: A library of universal knowledge |volume=5 |page=2399}}</ref> Downstream, it begins to define the border between the states of Nebraska and [[Missouri]], then flows between the states of Missouri and [[Kansas]]. The Missouri swings east at [[Kansas City, Missouri|Kansas City]], where the [[Kansas River]] enters from the west, and so on into north-central Missouri. To the east of Kansas City, the Missouri receives, on the left side, the [[Grand River (Missouri)|Grand River]]. It passes south of [[Columbia, Missouri|Columbia]] and receives the [[Osage River|Osage]] and [[Gasconade River|Gasconade]] Rivers from the south downstream of [[Jefferson City, Missouri|Jefferson City]]. The river then rounds the northern side of [[St. Louis, Missouri|St.&nbsp;Louis]] to join the Mississippi River on the border between Missouri and [[Illinois]].<ref name=topoquest/><ref name=ACMEmapper/>