By Madeline Heim, Milwaukee Journal Sentinel Jan 7, 2024

When you picture America's national parks and historic places, you might be thinking of the impressive Teton mountain range, the rock formations of Bryce Canyon or the geysers at Yellowstone.

But you can make your way through several sites of national importance just by following one of the nation's great rivers: the Mississippi.

Here, we've rounded up National Park Service sites and other federally protected places along the river. Visitors can hike, camp and fish in some, taking in the sweeping beauty of the river valley. Others offer a chance to get educated on the history of the Indigenous communities who lived near the river and, further south, a hard look at America's history of slavery.

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The Mississippi River watershed.

Milwaukee Journal Sentinel

What national parks, monuments and other spots are on the Mississippi River?

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10 key facts about the mighty Mississippi

The Mississippi River flows through 2,350 miles of America's heartland to the Gulf of Mexico. It provides habitat for hundreds of fish and wildlife species, charts the course of millions of tons of goods exported from the U.S. and has a rich cultural history, featured in many beloved books and songs.

It's facing big environmental challenges: nitrate and phosphorus pollution, forest loss, invasive species and prolonged and excessive flooding, to name a few. But it could also provide nature-based solutions to some of those problems, as scientists, politicians and citizens learn more about what can be done to protect it.

Here are 10 things to know about the iconic river that forms the nation’s largest watershed, spanning 31 states from Minnesota to Louisiana and Montana to Pennsylvania.

Where does the Mississippi River start and finish?

The Mississippi River begins as a small, knee-deep river flowing out of Lake Itasca in northwestern Minnesota. At just 18 feet wide, it's easy to walk across.

It flows hundreds of miles across Minnesota, including through the Twin Cities, before it reaches the Wisconsin border. Then it heads south, running alongside major cities like St. Louis, Memphis and New Orleans.

The river ends about 100 miles downstream from New Orleans, where it empties into the Gulf of Mexico. It takes 90 days for a single drop of water to travel from the headwaters to the Gulf.

What are the Mississippi River tributaries?

Some of the biggest tributaries that flow into the Mississippi include the Illinois, Missouri, Ohio, Arkansas and Red rivers.

How big is the Mississippi River basin?

The Mississippi River basin drains more than 40% of the continental U.S. In other words, any drop of rain or snow that falls across a large part of the country ends up in the Mississippi. It includes 31 states — some fully and some partially — and two Canadian provinces.

Because water travels over so much land before it reaches the Mississippi River, land use is an important determinant of the river's health. Industry and agriculture have both played a role in polluting the river, resulting in what's known as the Dead Zone in the Gulf of Mexico — a massive area where nutrient pollution chokes off oxygen for fish and plants.

Is the Mississippi River the longest river in the United States?

No. The Mississippi River flows about 2,350 miles, according to the National Park Service. The Missouri River flows about 100 miles longer, making it America's longest river.

The Missouri River stretches from the Rocky Mountains in southwest Montana to St. Louis, where it meets the Mississippi.

Both rivers' lengths can change slightly as their deltas grow or shrink from sedimentation or erosion. The Mississippi River delta in particular has lost approximately 70% of its land area since 1932 due to coastal erosion, sea level rise and human activities like oil and gas extraction.

Is it one of the longest rivers in the world?

Most lists of the world's longest rivers combine the Missouri and the Mississippi, since they join up. By that measure, the river is the fourth-longest in the world, behind the Nile, the Amazon and the Yangtze rivers.

By volume, the Mississippi River is the 15th-largest in the world. It discharges close to 600,000 cubic feet of water per second into the Gulf of Mexico, according to the National Park Service.

Where is the Mississippi River deepest?

The river's deepest point is near Algiers Point in New Orleans, measuring about 200 feet deep. That's a far cry from its depth at the headwaters, which is about 18 inches, according to the Minnesota Department of Natural Resources.

Do people drink from the Mississippi River?

Yes. The river provides drinking water for almost 20 million people in more than 50 municipalities, according to the environmental advocacy group American Rivers.

Is the Mississippi River drying out?

The Mississippi River is a major player in worldwide shipping and commerce. It carries around 500 million short tons per year of goods, including corn, soy, fertilizer, road salt, coal and petroleum products.

More than 90% of the nation's agricultural exports are grown in the Mississippi River basin; 60% of all grain exported from the U.S. is shipped on the river.

Periods of drought or flooding — which are expected to get more frequent as the climate changes — can stall shipping on the river. For example, near-record low water levels caused by drought caused barges to run aground on the lower Mississippi in fall 2022.

Is the Mississippi River important for wildlife?

The river ecosystem is vital for a wide variety of birds, fish and other animals. Each year, it provides a place to rest, breed and eat for more than 325 species of migrating birds. The upper Mississippi alone is home to over 119 species of fish, and its surrounding backwaters, wetlands and forests provide habitat for a multitude of other animals as well.

These important habitats are threatened by climate change and human activities. For example, prolonged and frequent flooding on the upper Mississippi caused by more precipitation and land use changes in the basin is killing floodplain forests and disturbing habitat for fish.

How did the Mississippi River get its name?

"Mississippi" comes from the French interpretation of the Ojibwe name for the river. That name was Misi-Ziibi, which means "great river."

The river is known by a variety of nicknames too, such as the Father of Waters.

— Madeline Heim, Milwaukee Journal Sentinel

In Minnesota, the Mississippi National River and Recreation Area is a 72-mile park full of opportunities for hiking, kayaking, bird-watching and learning about the river. According to its website, it's also home to the steepest descent of the river — more than 110 feet — through a narrow gorge.

Although it's not a National Park Service site, the Upper Mississippi River National Wildlife and Fish Refuge is not to be missed. The refuge stretches more than 260 river miles from Wabasha, Minnesota to Rock Island, Illinois, protecting more than 240,000 acres of river floodplain. During the right seasons, you can hunt, fish, hike, bird-watch and more.

Effigy Mounds National Monument, near Harpers Ferry, Iowa, is a sacred space for the Indigenous peoples who lived in the Mississippi River valley. More than 200 mounds are in the park, formed thousands of years ago by people of the Late Woodland period in the shapes of bears, birds and other animals. By taking the Fire Point loop on foot, visitors can see more than 25 mounds — including two effigy mounds, Little Bear and Great Bear — as well as expansive views of the river.

In St. Louis, Gateway Arch National Park is an iconic feature along the Mississippi River. The 630-foot stainless steel arch, which was completed in 1965, is built to withstand earthquakes and high winds. You can ride a tram to the top, which provides wide-ranging views of the river and the city.

In Natchez, Mississippi, Natchez National Historical Park is a place of hard truths about America's history of slavery. The wealth and charm of the river city "was built on a horrific international system of human trafficking of people of African descent," Park Superintendent Kathleen Bond wrote in a column. In 2021, the park marked the acknowledgment of Forks of the Road, once one of the largest places where people were sold into slavery across the south.

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Roads in the Driftless Area wind through the region's signature hills, which were beginning to show signs of fall colors.

Chelsey Lewis/Milwaukee Journal Sentinel

Could the Midwest get a national park on the Mississippi River?

There have been efforts to establish a national park in the Driftless region of Wisconsin, Minnesota, Iowa and Illinois, but they've faltered.

This past year, a proposal to create a Driftless National Park and Preserve in southeastern Minnesota was pulled after residents raised concerns about private land being made public and too many visitors harming the landscape, the Rochester Post-Bulletin reported in June.

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In a Facebook post announcing the idea was being rescinded, the author of the proposal wrote, "The core tenets of this idea of mine were efforts for the conservation of the Driftless ecosystem — an incredibly rich environment unlike anywhere else — and the preservation of this landscape for future generations."

In Alton, AltonWorks — a company that aims to revitalize the city's downtown — has proposed the creation of Great Rivers National Park, which would stretch 144 miles of riverfront.

A tug with several barges makes its way through Lock and Dam 16 on the Mississippi River near Muscatine, Iowa. Aerial support provided by LightHawk.

Nick Rohlman/Cedar Rapids Gazette

How locks and dams work

Get on a boat on the upper Mississippi River, and you'll eventually come upon a looming concrete structure stretching across the river's main channel.

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It's called a lock and dam, and it's a distinct feature of the upper river. The construction of locks and dams, a major feat of engineering that occurred largely during the Great Depression, has transformed how the Mississippi River runs.

What are these locks and dams for? How do they work, who controls them, and what changes have they made to the river ecosystem?

Here's what you should know.

The tug Theresa L. Wood heads upstream after locking through Lock and Dam 8.

Mark Hoffman/Milwaukee Journal Sentinel

Why are there locks and dams on the Mississippi River? How do they work?

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Prior to the installment of the locks and dams, the upper Mississippi River was free-flowing, regularly cutting new paths — and sometimes it was so shallow that people could wade across it. The locks and dams were put in place so that boats hauling freight up and down the upper river could have easier passage.

In 1930, Congress approved a project that would ultimately create the current system: The upper river is divided into sections called pools, where a fixed amount of river is held back by a dam. The U.S. Army Corps of Engineers controls how much water is in a pool at a given time. Each pool must be at least nine feet deep to allow towboats hauling barges to move through.

The construction of the locks and dams provided work for thousands of people along the upper river during the Great Depression. River towns grew in population as temporary workers moved in. An oral history project from the 1980s notes that in Genoa, Wisconsin, near Lock and Dam 8, "Business boomed, particularly taverns," and "Anyone having a room in a home had no trouble renting it."

Between the headwaters in northern Minnesota and St. Louis, the river falls about 420 feet in elevation. When a boat enters a lock, the lock acts like an elevator, bringing the boat up or down to the water level of the next pool. You can also picture it like a staircase of water that boats and barges climb and descend.

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Gearing installed in the mid-1930s that controls a roller gate is shown at a Mississippi River lock and dam.

Mark Hoffman/Milwaukee Journal Sentinel

Do the locks and dams control flooding on the river?

The locks and dams don't provide flood control. Downstream from Wisconsin, there are levees meant to constrain the river away from communities and high-production farmland.

The tug Theresa L. Wood heads upstream after locking through Lock and Dam 8.

Mark Hoffman/Milwaukee Journal Sentinel

How many locks and dams are there?

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There are 29 locks and dams on the upper river.

The first lock and dam structure, at Upper St. Anthony Falls in Minneapolis, has been closed to barge traffic since 2015. The Army Corps is considering the removal of the next two structures, Lower St. Anthony Falls Lock and Dam and Lock and Dam 1, between Minneapolis and St. Paul, to return the river to its free-flowing past in the Twin Cities.

The southernmost lock and dam is near Granite City in Illinois, north of St. Louis.

Who operates them?

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The Army Corps operates the locks and dams.

Why doesn't the lower Mississippi have locks and dams?

The lower river, which stretches south from Cairo, Illinois to the Gulf of Mexico, does not have locks and dams. As major rivers like the Missouri and the Ohio join up with the Mississippi, the channel becomes deep and wide enough to naturally accommodate shipping.

Are the locks and dams in good condition?

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When the locks and dams were constructed, mostly between 1930 and 1940, engineers estimated their lifespan to be about 50 years.

The Army Corps makes routine repairs to the structures, many of which still have original parts that are now around 90 years old. This winter, for example, they'll drain the water out of Lock and Dam 2 near Hastings, Minnesota, to make repairs to its concrete. But the Corps reports that there's an estimated billion-dollar maintenance backlog — and officials acknowledge that making fixes here and there may not be enough.

"At some point, we're going to need some major rehabilitation of these structures," Kristin Moe, navigation business line manager for the Army Corps' St. Paul District, told the Journal Sentinel earlier this year.

Groups that represent the shipping industry contend that instead of making repairs to existing locks, the Army Corps should be constructing new ones that have a 1,200-foot chamber to more efficiently accommodate larger groups of barges than the current chambers, which are 600 feet long.

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Bird-watchers gaze at tundra swans and other waterfowl on the Mississippi River from an overlook.

Mark Hoffman/Milwaukee Journal Sentinel

How have the locks and dams affected the river ecosystem?

Converting the free-flowing river into a series of pools has changed its natural habitats and processes. Because the dams caused more water to fill into the floodplain permanently, forest cover decreased and became fragmented, according to a 2022 study on the ecological status of the upper Mississippi.

Islands have shrunk or disappeared, attributed to wind and wave erosion across the pools, and backwater areas off of the main channel have filled in with sediment, making them less hospitable to fish. Consistent high water levels have made it more difficult for some types of aquatic vegetation to survive.

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In the decades since the locks and dams were constructed, the Army Corps has completed projects to try to address some of these consequences and revitalize habitat for fish and wildlife, including building new islands and dredging backwaters to restore their depth.

A pair of tundra swans fly above other waterfowl and swans on the Mississippi River.

Mark Hoffman/Milwaukee Journal Sentinel

How much trash does the river funnel

The Mississippi River drains more than 40% of the continental U.S. – just how much trash does it take along with it?

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That's what a group of researchers and environmental advocates wanted to find out when they began a litter analysis of a handful of cities along the river a few years ago. This fall, they released what they're calling the "first-ever snapshot of the state of plastic pollution along the Mississippi River."

Between 2021 and 2022, volunteers from St. Paul, Minnesota; the Quad Cities area in Iowa and Illinois; St. Louis, Missouri; Greenville and Rosedale, Mississippi; and Baton Rouge, Louisiana; logged trash they found into the University of Georgia's Debris Tracker app. The study came on the heels of a 2018 commitment from mayors along the river to reduce plastic and trash.

Although many people might think oceanside cities bear the responsibility to keep plastic and trash out of the water, the Mississippi River can act as a funnel for that trash from the heart of the country to the Gulf of Mexico.

The study was also meant to raise people's awareness of the river's role in keeping other waters clean, said Jennifer Wendt, plastic waste reduction campaign manager for the Mississippi River Cities and Towns Initiative — the mayors' group that worked on the study.

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For example, a piece of litter that someone tosses on the ground in Missouri could theoretically make its way through storm drains, to tributaries, to the Mississippi, to the Gulf and then to the ocean.

"It may not look like a plastic beverage bottle by the time it gets to the ocean, but it's still there," Wendt said.

Here's what to know about the study results, what's next for reducing plastic and trash along the river and how you can keep plastic out of important waterways.

Fog rises from the Mississippi River. Aerial support provided by LightHawk.

Nick Rohlman/Cedar Rapids Gazette

What was the top trash found in the Mississippi River?

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About 80,000 litter items were logged during the study's data collection period.

Plastic was the top material found in and around the river, making up 75% of the total trash. Paper and lumber was next at 9%, followed by metal at 7%, glass at 5%, and personal protective equipment like masks at 2%.

The top 10 most commonly found items included:

11,278 cigarette butts
9,809 food wrappers
6,723 beverage bottles
5,747 foam fragments
4,239 hard plastic fragments
4,210 paper and cardboard items
3,882 plastic bags
3,640 aluminum or tin cans
3,260 foam or plastic cups
3,149 film fragments

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Other notable finds include 825 masks, 480 items of clothing and shoes and 291 pieces of fishing gear.

In an optional survey after logging the trash they found, participants were asked if they cleaned it up. Close to three-fourths said yes.

What do the results tell us about litter habits?

People may not know that cigarette filters are made of cellulose acetate, a type of plastic, Wendt said. They can take up to 10 years to decompose. And cigarettes can also leach other toxic chemicals into the water, according to the report.

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Another intriguing finding was the amount of plastic beverage bottles and aluminum cans found, Wendt said — both of which are recyclable.

She noted that of the cities that took part in the study, only one of their states, Iowa, has a so-called "bottle bill," in which people pay a five-cent deposit when they purchase a beverage container and get a five-cent refund if they return the container to a store or redemption center. Bottles were lower down on the litter list in the Quad Cities than in other places.

Legislation like that "is not very popular politically," Wendt said, "but it does work."

Some states along the river prohibit local bans of plastic bags, she pointed out.

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What's next for keeping plastic out of the river?

River-wide data collection has wrapped up, but Wendt said the next step is carrying out city-specific projects to reduce plastic pollution.

Those include providing funds to underserved neighborhoods in St. Louis and Baton Rouge so they can pursue what they see as integral to reducing waste, like installing water-filling stations, or developing a curriculum for schools to teach about recycling.

The mayors' group will continue to work with the University of Georgia to do a comprehensive assessment of waste management in a few cities, Wendt said, and they're also planning to work with cities that don't have recycling programs to provide people a way to recycle.

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Wendt maintained that while recycling is part of the solution, it's not the only solution.

"(The discussion is) moving in the right direction, from 'Oh, we just need to clean up litter...' to, 'Oh, we actually need to reduce the source if we're going to have any real impact,'" she said.

What can people do to reduce plastic in waterways?

The biggest step people can take is to stop using plastic bags, Wendt said. That also goes for single-use plastic water bottles, she said, except for those who need to drink out of them because of water contamination.

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Beyond that, talk to local retailers and see if they'd be willing to ask customers if they want a bag instead of assuming they do, she said, and ask if restaurants could switch to sustainable materials for carryout containers and leftovers. Consumers can push retailers to make changes like this, she said, though she acknowledged it works best when people approach retailers as a group.

Nationally, Wendt said more attention is needed for the role the Mississippi River plays in carrying plastic and trash.

When she attends events about reducing plastic, representatives from coastal cities are often the only ones at the table.

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"There's this whole rest of the middle of the country that needs a little bit of focus," she said.

This story is a product of the Mississippi River Basin Ag & Water Desk, an independent reporting network based at the University of Missouri in partnership with Report for America, with major funding from the Walton Family Foundation