How big is Lake Sakakawea?

Lake Sakakawea, a vast reservoir in northwestern North Dakota, is one of the largest man-made lakes in the United States. Formed by the construction of Garrison Dam on the Missouri River, the lake stretches across several counties including McKenzie, Williams, Dunn, Mercer, Mountrail, and Ward. Its sheer size and significance in regional water management, recreation, and ecology make it a critical feature of the Northern Plains.

Dimensions and Surface Area

Lake Sakakawea spans an impressive length of approximately 178 miles (286 kilometers) from end to end, making it the third-largest reservoir in the United States by volume. At its widest point, the lake reaches about 14 miles (23 kilometers) across. The reservoir has more than 1,530 miles (2,460 kilometers) of shoreline—more than the California coastline.

The surface area of Lake Sakakawea can vary depending on water levels, but at its normal full pool elevation of around 1,850 feet (564 meters) above sea level, it covers approximately 307,000 acres (1,240 square kilometers). This size makes it the largest lake entirely within the state of North Dakota.

Water Volume and Capacity

In terms of volume, Lake Sakakawea has a total storage capacity of 23.8 million acre-feet of water. This vast quantity of water plays a major role in flood control, irrigation, navigation, hydropower generation, and municipal water supply throughout the Missouri River Basin.

Depth

The lake's depth also varies, with a maximum depth of approximately 180 feet (55 meters) near the dam. The depth decreases gradually upstream, where the lake becomes shallower and more river-like in appearance.

Comparison with Other U.S. Reservoirs

Lake Sakakawea is often compared with other large reservoirs in the United States, such as Lake Mead (on the Colorado River) and Lake Powell (on the Arizona-Utah border). While Lake Sakakawea is not the largest in terms of surface area, it rivals others in overall water storage capacity and is notable for its long, narrow shape that follows the contours of the pre-existing Missouri River valley.

Conclusion

Lake Sakakawea is a monumental body of water whose size reflects its importance. With over 300,000 acres of surface area, nearly 24 million acre-feet of water storage, and more shoreline than the Pacific Coast of the contiguous U.S., this reservoir is a cornerstone of life in North Dakota. Its vast dimensions not only make it a hub for recreation and wildlife habitat but also a vital piece of infrastructure for water management across a broad swath of the American Midwest.