Red River of the North in the context of "Lake Winnipeg"

The Red River is a major river in the Southern United States. It was named for its reddish water color from passing through red-bed country in its watershed. It also is known as the Red River of the South to distinguish it from the Red River of the North, which flows between Minnesota and North Dakota into the Canadian province of Manitoba. Although once a tributary of the Mississippi River, the Red River now is a tributary of the Atchafalaya River, a distributary of the Mississippi that flows separately into the Gulf of Mexico. This confluence is connected to the Mississippi River by the Old River Control Structure.

The south bank of the Red River formed part of the US–Mexico border from the Adams–Onís Treaty (in force only in 1821), until the Texas Annexation and the Treaty of Guadalupe Hidalgo.

Winnipeg (/ˈwɪnɪpɛɡ/ ) is the capital and largest city of the Canadian province of Manitoba. It is centred on the confluence of the Red and Assiniboine rivers. As of 2021, Winnipeg had a city population of 749,607 and a metropolitan population of 834,678, making it Canada's sixth-largest city and eighth-largest metropolitan area.

The city is named after the nearby Lake Winnipeg; the name "Winnipeg" comes from the Western Cree words for "muddy water" – winipīhk. The region was a trading centre for Indigenous peoples long before the arrival of Europeans; it is the traditional territory of the Anishinaabe (Ojibway), Ininew (Cree), Oji-Cree, Dene, and Dakota, and is the birthplace of the Métis Nation. French traders built the first fort, Fort Rouge, on the site in 1738. A settlement was later founded by the Selkirk settlers of the Red River Colony in 1812, the nucleus of which was incorporated as the City of Winnipeg in 1873. Being far inland, the city's climate is extremely seasonal (continental) even by Canadian standards, with average January highs of around −11 °C (12 °F) and average July highs of 26 °C (79 °F).

The longest rivers of the United States include 38 that have main stems of at least 500 miles (800 km) long. The main stem is "the primary downstream segment of a river, as contrasted to its tributaries". The United States Geological Survey (USGS) defines a main-stem segment by listing coordinates for its two end points, called the source and the mouth. Some well-known rivers like the Atchafalaya, Willamette, and Susquehanna are not included in this list because their main stems are shorter than 500 miles.

Seven rivers in this list cross or form international boundaries. Three—the Milk River, the Red River of the North, and the Saint Lawrence River—begin in the United States and flow into Canada; two do the opposite (Yukon and Columbia). Also a segment of the Saint Lawrence River forms the international border between part of the province of Ontario, Canada, and the U.S. state of New York. Of these seven rivers, only the Milk River crosses the international border twice, leaving and then re-entering the United States. Two rivers, the Colorado and the Rio Grande, begin in the United States and flow into or form a border with Mexico. In addition, the drainage basins of the Mississippi and Missouri rivers extend into Canada, and the basin of the Gila River extends into Mexico.

Title 33 of the United States Code outlines the role of navigable waters in the United States Code.

• 33 U.S.C. ch. 1—Navigable Waters Generally
• 33 U.S.C. ch. 2—International Rules for Navigation at Sea
• 33 U.S.C. ch. 3—Navigation Rules for Harbors, Rivers, and Inland Waters Generally
• 33 U.S.C. ch. 4—Navigation Rules for Great Lakes and Their Connecting and Tributary Waters
• 33 U.S.C. ch. 5—Navigation Rules for Red River of the North and Rivers Emptying Into Gulf of Mexico and Tributaries
• 33 U.S.C. ch. 5A—Exemption of Navy Or Coast Guard Vessels from Certain Navigation Rules
• 33 U.S.C. ch. 6—General Duties of Ship Officers and Owners After Collision or Other Accident
• 33 U.S.C. ch. 7—Regulations For the Suppression of Piracy
• 33 U.S.C. ch. 8—Summary Trials For Certain Offenses Against Navigation Laws
• 33 U.S.C. ch. 9—Protection of Navigable Waters and of Harbor and River Improvements Generally
• 33 U.S.C. ch. 10—Anchorage Grounds And Harbor Regulations Generally
• 33 U.S.C. ch. 11—Bridges Over Navigable Waters
• 33 U.S.C. ch. 12—River and Harbor Improvements Generally
• 33 U.S.C. ch. 13—Mississippi River Commission
• 33 U.S.C. ch. 14—California Debris Commission
• 33 U.S.C. ch. 15—Flood Control
• 33 U.S.C. ch. 16—Lighthouses
• 33 U.S.C. ch. 17—National Ocean Survey
• 33 U.S.C. ch. 18—Longshore and Harbor Workers Compensation
• 33 U.S.C. ch. 19—Saint Lawrence Seaway
• 33 U.S.C. ch. 20—Pollution of the Sea by Oil
• 33 U.S.C. ch. 21—International Regulations for Preventing Collisions at Sea
• 33 U.S.C. ch. 22—Sea Grant Colleges and Marine Science Development
• 33 U.S.C. ch. 23—Pollution Control of Navigable Waters
• 33 U.S.C. ch. 24—Vessel Bridge-To-Bridge Communication
• 33 U.S.C. ch. 25—Ports and Waterways Safety Program
• 33 U.S.C. ch. 26—Water Pollution Prevention and Control
• 33 U.S.C. ch. 27—Ocean Dumping
• 33 U.S.C. ch. 28—Pollution Casualties on the High Seas: United States Intervention
• 33 U.S.C. ch. 29—Deepwater Ports
• 33 U.S.C. ch. 30—International Regulations for Preventing Collisions at Sea
• 33 U.S.C. ch. 31—Ocean Pollution Research and Development and Monitoring Planning
• 33 U.S.C. ch. 32—Inland Waterways Trust Fund
• 33 U.S.C. ch. 33—Prevention of Pollution from Ships
• 33 U.S.C. ch. 34—Inland Navigational Rules
• 33 U.S.C. ch. 35—Artificial Reefs
• 33 U.S.C. ch. 36—Water Resources Development
• 33 U.S.C. ch. 37—Organotin Antifouling Paint Control
• 33 U.S.C. ch. 38—Dumping of Medical Waste by Public Vessels
• 33 U.S.C. ch. 39—Shore Protection from Municipal or Commercial Waste
• 33 U.S.C. ch. 40—Oil Pollution
• 33 U.S.C. ch. 41—National Coastal Monitoring
• 33 U.S.C. ch. 42—Estuary Restoration
• 33 U.S.C. ch. 43—National Oceanic and Atmospheric Administration Commissioned Officer Corps
• 33 U.S.C. ch. 44—Oceans and Human Health

Moorhead (/ˈmɔːrhɛd/ MOR-hed) is a city in and the county seat of Clay County, Minnesota, United States, on the banks of the Red River of the North. Located in the Red River Valley, an extremely fertile and active agricultural region, Moorhead is home to several corporations and manufacturing industries. Across the river from Fargo, North Dakota and next to Dilworth, Minnesota, Moorhead forms part of the core of the Fargo–Moorhead ND-MN Metropolitan Area. The population was 44,505 at the 2020 census. Moorhead is a hub of higher education in Minnesota, home to Minnesota State University Moorhead, Concordia College, and a campus of Minnesota State Community and Technical College.

Platted in 1871, the city was named for William Galloway Moorhead, an official of the Northern Pacific Railway.

Fargo is the most populous city in the U.S. state of North Dakota. The population was 125,990 at the 2020 census and estimated at 136,285 in 2024. Fargo and its twin city of Moorhead, Minnesota, form the core of the Fargo–Moorhead metropolitan area, which had a population of 248,591 in 2020. It is the county seat of Cass County.

Fargo was founded in 1871 on the Red River of the North floodplain. It is a cultural, retail, health care, educational, and industrial center for southeastern North Dakota and northwestern Minnesota. North Dakota State University is in the city.

The Assiniboine River (/əˈsɪnɪbɔɪn/ ə-SIN-ih-boyn; French: Rivière Assiniboine) is a 1,070-kilometre (660 mi) long river that runs through the prairies of Western Canada in Saskatchewan and Manitoba. It is a tributary of the Red River. The Assiniboine is a typical meandering river with a single main channel embanked within a flat, shallow valley in some places and a steep valley in others. Its main tributaries are the Qu'Appelle, Souris, and Whitesand Rivers.

The river takes its name from the Assiniboine, a First Nations peoples of the northern Great Plains. Robert Douglas of the Geographical Names Board of Canada (1933) made several comments as to its origin: "The name commemorates the Assiniboine natives called by La Vérendrye in 1730 'Assiniboils' and by Governor Knight in 1715 of the Hudson's Bay Company 'stone Indians.' Assiniboine is the name of an Indian tribe and is derived from 'assine' a stone and 'bwan' native name of the Sioux, hence Stony Sioux name was possibly given because they used heated stones in cooking their food."

A low-water crossing (also known as an Irish bridge or Irish Crossing, causeway in Australia, low-level crossing or low-water bridge) is a low-elevation roadway traversing over a waterbody that stays dry above the water when the flow is low, but is designed to be submerged under high-flow conditions such as floods. This type of crossing is much cheaper to build than a high bridge that keeps the road surface consistently above the highest water level, and is usually deployed in semi-arid areas where high-volume rainfall is rare and the existing channel is shallow (which requires extra ramping on the banks to build a more elevated bridge and thus costs more), particularly in developing countries.

Low-water crossings are essentially elevated floodways, functioning like causeways under normal conditions and serving as limited fords during high-discharge conditions. They are generally considered unsafe for traffic during floods due to the potentially fast and turbulent currents flowing over the road surface, and can be dangerous even after the flood has receded because silt, mud and debris left on the road by the water can reduce traction and cause skidding risks for both vehicles and pedestrians.