Mississippi River in the context of "Blue catfish"

A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, the drainage divide, made up of a succession of elevated features, such as ridges and hills. A basin may consist of smaller basins that merge at river confluences, forming a hierarchical pattern.

Other terms for a drainage basin are catchment area, catchment basin, drainage area, river basin, water catchment, water basin, and impluvium. In North America, they are commonly called a watershed, though in other English-speaking places, "watershed" is used only in its original sense, that of the drainage divide line.

St. Louis (/seɪnt ˈluːɪs, sənt-/ saynt LOO-iss, sənt-, sometimes referred to as St. Louis City, Saint Louis or STL) is an independent city in the U.S. state of Missouri. It lies near the confluence of the Mississippi and the Missouri rivers. In 2020, the city proper had a population of 301,578, while its metropolitan area, which extends into Illinois, had an estimated population of over 2.8 million. It is the largest metropolitan area in Missouri and the second-largest in Illinois. The city's combined statistical area is the 20th-largest in the United States.

The land that became St. Louis had been occupied by Native American cultures for thousands of years before European settlement. The city was founded on February 14, 1764, by French fur traders Gilbert Antoine de St. Maxent, Pierre Laclède, and Auguste Chouteau. They named it for King Louis IX of France, and it quickly became the regional center of the French Illinois Country. In 1804, the United States acquired St. Louis as part of the Louisiana Purchase. In the 19th century, St. Louis developed as a major port on the Mississippi River; from 1870 until the 1920 census, it was the fourth-largest city in the country. It separated from St. Louis County in 1877, becoming an independent city and limiting its political boundaries. In 1904, it hosted the Louisiana Purchase Exposition, also known as the St. Louis World's Fair, and the Summer Olympics.

Minneapolis is a city in Hennepin County, Minnesota, United States, and its county seat. With a population of 429,954 as of the 2020 census, it is the state's most populous city. Located in the state's center near the eastern border, it occupies both banks of the Upper Mississippi River and adjoins Saint Paul, the state capital of Minnesota. Minneapolis, Saint Paul, and the surrounding area are collectively known as the Twin Cities, a metropolitan area with 3.69 million residents. Minneapolis is built on an artesian aquifer on flat terrain and is known for cold, snowy winters and hot, humid summers. Nicknamed the "City of Lakes", Minneapolis is abundant in water, with thirteen lakes, wetlands, the Mississippi River, creeks, and waterfalls. The city's public park system is connected by the Grand Rounds National Scenic Byway.

Dakota people previously inhabited the site of today's Minneapolis. European colonization and settlement began north of Fort Snelling along Saint Anthony Falls—the only natural waterfall on the Mississippi River. Location near the fort and the falls' power—with its potential for industrial activity—fostered the city's early growth. For a time in the 19th century, Minneapolis was the lumber and flour milling capital of the world, and as home to the Federal Reserve Bank of Minneapolis, it has preserved its financial clout into the 21st century. A Minneapolis Depression-era labor strike brought about federal worker protections. Work in Minneapolis contributed to the computing industry, and the city is the birthplace of General Mills, the Pillsbury brand, Target Corporation, and Thermo King mobile refrigeration.

The St. Lawrence River (French: Fleuve Saint-Laurent, pronounced [flœv sɛ̃ lɔʁɑ̃]) is a large international river in the middle latitudes of North America connecting the Great Lakes to the North Atlantic Ocean. Its waters flow in a northeasterly direction from Lake Ontario to the Gulf of St. Lawrence, traversing Ontario and Quebec in Canada and New York in the United States. A section of the river demarcates the Canada–U.S. border.

As the primary drainage outflow of the Great Lakes Basin, the St. Lawrence has the second-highest discharge of any river in North America (after the Mississippi River) and the 16th-highest in the world. The estuary of the St. Lawrence is often cited by scientists as the largest in the world. Significant natural landmarks of the river and estuary include the 1,864 river islands of the Thousand Islands, the endangered whales of Saguenay–St. Lawrence Marine Park, and the limestone monoliths of the Mingan Archipelago.

The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes spanning the Canada–United States border. The five lakes are Superior, Michigan, Huron, Erie, and Ontario (though hydrologically, Michigan and Huron are a single body of water, joined at the Straits of Mackinac). The Great Lakes Waterway enables modern travel and shipping by water among the lakes. The lakes connect ultimately to the Atlantic Ocean via the Saint Lawrence River as their primary drainage outflow. The lakes are also connected to the Mississippi River basin through the Illinois Waterway.

The Great Lakes are the largest group of freshwater lakes on Earth by total area and the second-largest by total volume. They contain 21% of the world's surface fresh water by volume. The total surface is 94,250 square miles (244,106 km), and the total volume (measured at the low water datum) is 5,439 cubic miles (22,671 km), slightly less than the volume of Lake Baikal (5,666 cu mi or 23,615 km, 22–23% of the world's surface fresh water). Because of their sea-like characteristics, such as rolling waves, sustained winds, strong currents, great depths, and distant horizons, the five Great Lakes have long been called inland seas. Depending on how it is measured, by surface area, either Lake Superior or Lake Michigan–Huron is the second-largest lake in the world and the largest freshwater lake. Lake Michigan is the largest lake, by surface area, that is entirely within one country, the United States.

The Mississippi River System, also referred to as the Western Rivers, is a mostly riverine network of the United States which includes the Mississippi River and connecting waterways. The Mississippi River is the largest drainage basin in the United States. In the United States, the Mississippi drains about 41% of the country's rivers.

From the perspective of natural geography and hydrology, the system consists of the Mississippi River itself and its numerous natural tributaries and distributaries. The major tributaries are the Arkansas, Illinois, Missouri, Ohio and Red rivers. Given their flow volumes, major Ohio River tributaries like the Allegheny, Tennessee, and Wabash rivers are considered important tributaries to the Mississippi system. Before the Mississippi River reaches the Gulf of Mexico, it runs into its distributary, the Atchafalaya River.

Vermont (/vərˈmɒnt/ ) is a landlocked state in the New England region of the Northeastern United States. It borders Massachusetts to the south, New Hampshire to the east, New York to the west, and the Canadian province of Quebec to the north. According to the most recent U.S. census estimates, the state has an estimated population of 648,493, making it the second-least populated of all U.S. states. It is the nation's sixth-smallest state by total area. The state's capital of Montpelier is the least populous U.S. state capital. No other U.S. state has a most populous city with fewer residents than Burlington.

Native Americans have inhabited the area for about 12,000 years. The competitive tribes of the Algonquian-speaking Abenaki and Iroquoian-speaking Mohawk were active in the area at the time of European encounter. During the 17th century, French colonists claimed the territory as part of New France. Conflict arose when the Kingdom of Great Britain began to settle colonies to the south along the Atlantic coast; France was defeated in 1763 in the Seven Years' War, ceding its territory east of the Mississippi River to Britain. Thereafter, the nearby British Thirteen Colonies disputed the extent of the area called the New Hampshire Grants to the west of the Connecticut River, encompassing present-day Vermont. The provincial government of New York sold land grants to settlers in the region, which conflicted with earlier grants from the government of New Hampshire. The Green Mountain Boys militia protected the interests of the established New Hampshire land grant settlers. Ultimately, a group of settlers with New Hampshire land grant titles established the Vermont Republic in 1777 as an independent state during the American Revolutionary War. The Vermont Republic abolished slavery before any other U.S. state. It was admitted to the Union in 1791 as the 14th state.

Chicago is the most populous city in the U.S. state of Illinois and in the Midwestern United States. Located on the western shore of Lake Michigan, it is the third-most populous city in the United States, with a population of 2.74 million at the 2020 census. The Chicago metropolitan area has 9.41 million residents and is the third-largest metropolitan area in the country. Chicago is the seat of Cook County, the second-most populous county in the U.S.

Chicago was incorporated as a city in 1837 near a portage between the Great Lakes and the Mississippi River watershed. It grew rapidly in the mid-19th century. In 1871, the Great Chicago Fire destroyed several square miles and left more than 100,000 homeless, but Chicago's population continued to grow. Chicago made noted contributions to urban planning and architecture, such as the Chicago School, the development of the City Beautiful movement, and the steel-framed skyscraper.

Illinois (/ˌɪlɪˈnɔɪ/ IL-ih-NOY) is a state in the Midwestern region of the United States. It borders Lake Michigan to its northeast, the Mississippi River to its west, and the Wabash and Ohio rivers to its south. Of the fifty U.S. states, Illinois has the fifth-largest gross domestic product (GDP), the sixth-largest population, and the 25th-most land area. Its capital city is Springfield in the center of the state, and the state's largest city is Chicago in the northeast.

Present-day Illinois was inhabited by Indigenous cultures for thousands of years. The French were the first Europeans to arrive, settling near the Mississippi and Illinois rivers in the 17th century Illinois Country, as part of their sprawling colony of New France. A century later, the revolutionary war Illinois campaign prefigured American involvement in the region. Following U.S. independence in 1783, which made the Mississippi River the national boundary, American settlers began arriving from Kentucky via the Ohio River. Illinois was soon part of the United States' oldest territory, the Northwest Territory, and in 1818 it achieved statehood. The Erie Canal brought increased commercial activity in the Great Lakes, and the invention of the self-scouring steel plow by Illinoisan John Deere turned the state's rich prairie into some of the world's most productive and valuable farmland, attracting immigrant farmers from Germany, Sweden and elsewhere. In the mid-19th century, the Illinois and Michigan Canal and a sprawling railroad network facilitated trade, commerce, and settlement, making the state a transportation hub for the nation, especially in the city of Chicago, which became the world's fastest growing city by the late 19th century. By 1900, the growth of industrial jobs in the northern cities and coal mining in the central and southern areas attracted immigrants from Eastern and Southern Europe. Illinois became one of America's most industrialized states and remains a major manufacturing center. The Great Migration from the South established a large Black community, particularly in Chicago, which became a leading cultural, economic, and population center; its metropolitan area, informally referred to as Chicagoland, holds about 65% of the state's 12.8 million residents.

The United States Army Corps of Engineers (USACE) is the military engineering branch of the United States Army. A direct reporting unit (DRU), it has three primary mission areas: Engineer Regiment, military construction, and civil works. USACE has 37,000 civilian and military personnel, making it one of the world's largest public engineering, design, and construction management agencies. The USACE workforce is approximately 97% civilian, 3% active duty military. The civilian workforce is mainly located in the United States, Europe and in select Middle East office locations. Civilians do not function as active duty military and are not required to be in active war and combat zones; however, volunteer (with pay) opportunities do exist for civilians to do so.

The day-to-day activities of the three mission areas are administered by a lieutenant general known as the chief of engineers/commanding general. The chief of engineers commands the Engineer Regiment, comprising combat engineer, rescue, construction, dive, and other specialty units, and answers directly to the chief of staff of the Army. Combat engineers, sometimes called sappers, form an integral part of the Army's combined arms team and are found in all Army service components: Regular Army, National Guard, and Army Reserve. Their duties are to breach obstacles; construct fighting positions, fixed/floating bridges, and obstacles and defensive positions; place and detonate explosives; conduct route clearance operations; emplace and detect landmines; and fight as provisional infantry when required. For the military construction mission, the chief of engineers is directed and supervised by the Assistant Secretary of the Army for installations, environment, and energy, whom the President appoints and the Senate confirms. Military construction relates to construction on military bases and worldwide installations.