The Largest Man-Made Lakes in the United States

The United States is home to some of the largest man-made lakes in the world, providing water supply, flood control, hydroelectric power, and recreational activities for millions of people.

These massive reservoirs serve as vital resources and offer some of the most scenic and exciting destinations for travelers, outdoor enthusiasts, and nature lovers. Whether you’re into fishing, boating, or just exploring natural landscapes, the largest man-made lakes in the United States have something for everyone.

In this detailed blog, we’ll explore the largest man-made lakes in the U.S., examining their history, primary purpose, and recreational potential. From the iconic Lake Mead to the sprawling Fort Peck Lake, these bodies of water are engineering marvels that help define the landscape of the United States.

1. Lake Mead (Nevada/Arizona)

Lake Mead, located on the Colorado River between Nevada and Arizona, is the largest man-made reservoir in the United States by total capacity. Formed by the construction of the Hoover Dam in the 1930s, it has a surface area of 247 square miles (640 square kilometers) and a total water capacity of over 26 million acre-feet.

Lake Mead is critical in water supply, providing water to Las Vegas and Los Angeles. The reservoir also supports flood control and hydroelectric power generation via the Hoover Dam. Its water levels have fluctuated in recent years due to drought, but the lake remains a popular destination for boating, fishing, and water sports.

With nearly 700 miles of shoreline, Lake Mead is ideal for hiking, camping, and exploring sandy beaches. Anglers often target species like striped bass, largemouth bass, and channel catfish, while birdwatchers can spot various migratory birds around the lake.

2. Lake Oahe (North Dakota/South Dakota)

Stretching across two states, Lake Oahe is one of the largest man-made lakes in the United States by surface area. This enormous reservoir covers approximately 370,000 acres (1,500 square kilometers) and was created by the Oahe Dam on the Missouri River in South Dakota in the 1960s.

The lake’s primary purpose is flood control, water supply, and hydroelectric power generation. It has a maximum depth of around 205 feet (62 meters) and provides a major recreational outlet for residents and visitors alike. With 2,250 miles of shoreline, Lake Oahe offers endless fishing, boating, and camping opportunities. The lake is famous for its walleye fishing, with northern pike and chinook salmon also being popular catches.

Lake Oahe’s vastness makes it a top spot for water-based recreation, and its natural landscapes draw outdoor adventurers. The Garrison Dam, which created Lake Oahe, is also an impressive site and part of the Missouri River’s extensive system of dams.

3. Lake Sakakawea (North Dakota)

Located entirely in North Dakota, Lake Sakakawea is another massive man-made reservoir on the Missouri River. It covers a total surface area of around 307,000 acres (1,240 square kilometers) and holds over 23 million acre-feet of water. The lake was created in the 1950s following the construction of the Garrison Dam, the fifth-largest dam in the world in terms of material volume.

Lake Sakakawea is known for its role in flood management, water supply, and hydroelectric power generation. The lake’s recreational opportunities are endless, with fishing being a favorite activity. Anglers can expect to find walleye, northern pike, and chinook salmon in the lake’s waters.

With 1,320 miles of shoreline, Lake Sakakawea offers many options for boating, camping, and hiking. The lake is also a habitat for migratory birds, making it a top spot for birdwatching.

4. Lake Powell (Arizona/Utah)

Lake Powell, formed by the Glen Canyon Dam on the Colorado River, is one of the most scenic and popular man-made lakes in the United States. With a surface area of 254 square miles (660 square kilometers), Lake Powell is the second-largest reservoir in the U.S. by capacity, holding over 24 million acre-feet of water at the entire pool.

Lake Powell is famous for its striking red rock landscapes and recreational opportunities. The lake’s 1,900 miles of shoreline are dotted with sandy beaches, perfect for camping, sunbathing, and picnicking. Boating, kayaking, and water skiing are extremely popular here, with houseboats often cruising the lake’s crystal-clear waters.

Anglers come to Lake Powell for its diverse fish species, including striped bass, largemouth bass, and catfish. The lake also draws visitors who come to explore its hidden canyons, coves, and rock formations, making it a prime spot for adventure.

5. Fort Peck Lake (Montana)

Fort Peck Lake is located in northeastern Montana and was created by constructing the Fort Peck Dam, one of the largest dams in the world. Covering an area of 245,000 acres (990 square kilometers), Fort Peck Lake is one of the largest reservoirs in the United States by surface area.

Fort Peck Lake serves important purposes, including flood control, hydroelectric power generation, and water supply. The lake has a maximum length of 134 miles (216 kilometers) and offers a variety of recreational activities. Fishing enthusiasts flock to the lake for walleye, northern pike, and smallmouth bass.

The lake’s remote location makes it a peaceful destination for camping, hiking, and birdwatching. With over 1,500 miles of shoreline, Fort Peck Lake is a true outdoor paradise, offering pristine natural landscapes for visitors to explore.

6. Lake Mead’s Rivals: Global Competitors

While Lake Mead is the largest man-made lake in the United States, it pales compared to some massive reservoirs worldwide. Lake Kariba, located on the border of Zambia and Zimbabwe, is the world’s largest man-made lake by volume, holding a staggering 180 cubic kilometers of water. Similarly, the Bratsk Reservoir in Russia, with a surface area of 5,470 square kilometers, surpasses any man-made body of water in the U.S.

Another international giant is Lake Volta in Ghana, which was created by the construction of the Akosombo Dam. Covering 3,275 square miles (8,502 square kilometers), Lake Volta is the largest man-made lake in the world by surface area. These vast bodies of water showcase the scale of human engineering globally.

7. Honorable Mentions: More Man-Made Marvels in the U.S.

Several other man-made lakes across the United States deserve mention for their size and significance:

– Lake Okeechobee (Florida): Though technically a natural freshwater lake, it has been extensively modified for flood control and irrigation. Covering over 730 square miles (1,890 square kilometers), it’s one of the largest freshwater lakes in the U.S.

Grand Coulee Dam Reservoir (Washington)**: Formed by the Grand Coulee Dam, this reservoir is a key player in irrigation, power generation, and recreation. It’s another example of human ingenuity in water management.

– Lake Erie, Lake Huron, and the Great Lakes: Although not man-made, these massive freshwater lakes are worth mentioning due to their sheer size. The Great Lakes hold about 20% of the world’s fresh surface water and are vital to the environment and economy.

8. Man-Made Lakes: More Than Just Water

Man-made lakes in the United States are not only feats of engineering but also provide countless recreational and environmental benefits. From water supply and flood control to hydroelectric power generation, these reservoirs serve vital purposes for millions of people. At the same time, they are home to diverse ecosystems, offering habitat for fish species, migratory birds, and other wildlife.

For those who love the outdoors, these lakes offer miles of shoreline, pristine natural landscapes, and countless activities. Whether casting a line for a northern pike in Lake Sakakawea or cruising the waters of Lake Powell on a houseboat, these man-made bodies of water offer unique experiences and adventures.

In conclusion, the largest man-made lakes in the United States are much more than just reservoirs. They are integral to the country’s water management systems and beloved recreational destinations. With their expansive waters, beautiful surroundings, and vast recreational opportunities, these lakes perfectly balance human innovation and nature’s beauty.