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One of the largest natural lakes in the state, Lake Poinsett is of glacial origin, a meandered lake with its waters state owned, and its fishery managed by the SDGFP.

Lake Poinsett is part of a chain of connected lakes. It receives most water inflows directly from the Dry Lake subwatershed to the north and from Lake Albert.

Miles of Shoreline.....................15 miles

Surface Area of Water ........ 7,903 acres

Watershed Area ............. 292,197 acres

Maximum Depth................... ... 22 feet

Mean Depth .......................... ..17 feet

Ordinary High-Water Mark (OHWM) 1651.5 fmsl


SDGFP maintains five developed public accesses on the lake: Sorenson, Saaranen, Hammer's Beach, Prestrudes, and the State Recreation Area.

Lake Poinsett State Recreation Area is located on the Southeast side in Brookings County for public camping and day use.




459th Ave Outlet Control Structure (Gate)

Within the watershed, water runs through a chain-of-lakes and finally into Lake Poinsett, its single natural outlet is three miles long to its entrance into the Big Sioux River. Lake Poinsett’s outlet channels water under the HWY 28 bridge (northeast section of the lake) and under the 459th Avenue bridge.

After flooding in 1986, the natural outlet of Lake Poinsett was modified to include a control structure to prevent the backflow of high waters from the Big Sioux River into the lake. The structure was completed in 1989 and constructed to an elevation of 1,650.5 feet above mean sea level (msl), one foot below the Lake Poinsett ordinary high-water mark of 1,651.5 msl.

These outlet gates beneficially affect the lake’s water quality, water flow, and lake level. The river holds pollutants and high nutrient levels that could harm the lake’s clean qualities enjoyed by all and reverse the collaborative environmental efforts by many organizations. The Sioux City Journal (May 7, 2012) reported that the advocacy group, Environment America, ranked the Big Sioux River as the nation's 13th dirtiest river.

The permanent outlet gate is maintained and operated by the Lake Poinsett Water Project District, who strictly adheres to specific rules documented and regulated by the South Dakota Water Management Board.

  • Gates Closed - when the Big Sioux is higher than lake.

  • Gates Open - when the lake is higher.


Joel Roberts Poinsett

In 1838, the Lake Poinsett area was visited by the expedition of Joseph Nicollet and John Fremont, who camped on the lake's north shore. The two explorers named our gem of a lake after the U.S. Secretary of War, Joel Roberts Poinsett, who was instrumental in funding their expedition.

Read more on Joel Roberts Poinsett

View Hall of Fame video on Joel Roberts Poinsett.

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