Does North Dakota’s Lake Sakakawea give the state more 'shoreline' than California?

No.

Lake Sakakawea, a large reservoir on the Missouri River in North Dakota, is often cited in claims that the state has more shoreline than California.

At full pool, Lake Sakakawea’s total shoreline is estimated at roughly 1,300 to 1,500 miles, depending on water levels. That is substantial for a single inland body of water and does exceed the length of California’s general coastline, which is about 840 miles when measured along the Pacific Ocean.

However, California’s total coastal shoreline is far longer when bays, estuaries, islands, and tidal inlets are included. Using standard shoreline measurements that account for these features, California has more than 3,400 miles of shoreline. In addition, that figure reflects only coastal shoreline and does not include inland lakes and reservoirs. California has more than 3,000 named lakes, reservoirs, and dry lakes.

North Dakota’s total shoreline, even including Lake Sakakawea, Devils Lake and other water bodies, is estimated at about 2,500 miles.

The faulty comparison relies on mixing different measurement methods, which makes the claim misleading.

This fact brief is responsive to conversations such as this one.

Sources:

Wikipedia: Lake Sakakawea
National Oceanic and Atmospheric Administration: Shoreline Mileage of the United States
California Coastal Commission: California’s Coast
U.S. Army Corps of Engineers Omaha District: Garrison Dam and Lake Sakakawea
Recreation.gov: Sakakawea Lake
California Water Board: Monitoring Monday