Reservoirs in Wisconsin

93 of 158 graded Wisconsin lakes (59%) are man-made reservoirs in the USACE National Inventory of Dams. 55 carry a High or Significant hazard rating.

Why these Wisconsin reservoirs were built

Recreation

Flood Risk Reduction

Fish and Wildlife Pond

Water Supply

Other

Hydroelectric

Irrigation

Total reservoirs

567,652

Total surface acres

40,454,014

Normal storage (ac-ft)

High or Significant hazard

All 93 Wisconsin reservoirs (by surface area)

Reservoir	County	Grade	Surface area	Year built	Purpose	Hazard
Devils Lake	Ramsey	C	140,000 ac	1997	Flood Risk Reduction	High
Qacmainstdup Lake	Mercer	B	133,000 ac	1953	Hydroelectric	High
Qacmainstfbk Lake	Mercer	A	133,000 ac	1953	Hydroelectric	High
Lake Audubon	McLean	B	19,095 ac	1952	Other	Significant
Jamestown Reservoir	Stutsman	D	17,427 ac	1954	Flood Risk Reduction	High
Jamestown Reservoir	Stutsman	B	17,427 ac	1954	Flood Risk Reduction	High
Lake Tschida	Grant	C	10,953 ac	1949	Flood Risk Reduction	High
Lake Tschida	Grant	C	10,953 ac	1949	Flood Risk Reduction	High
Lake Tschida	Grant	C	10,953 ac	1949	Flood Risk Reduction	High
Lake Tschida	Grant	C	10,953 ac	1949	Flood Risk Reduction	High
Lake Tschida	Grant	C	10,953 ac	1949	Flood Risk Reduction	High
Lake Darling	Ward	D	9,655 ac	1937	Fish and Wildlife Pond	High
Lake Darling	Renville	B	9,655 ac	1937	Fish and Wildlife Pond	High
Lake Ashtabula	Barnes	B	5,470 ac	1950	Flood Risk Reduction	High
J. Clark Salyer Pool 357	Bottineau	F	5,001 ac	1936	Fish and Wildlife Pond	Low
Lake Alice	Ramsey	D	3,067 ac	1942	Fish and Wildlife Pond	Low
E. A. Patterson Lake	Stark	D	2,158 ac	1950	Irrigation	High
Bowman-Haley Dam Lake	Bowman	C	1,750 ac	1967	Flood Risk Reduction	High
Lake Metigoshe	Bottineau	C	1,620 ac	1961	Recreation	Low
Buffalo Lodge Lake	McHenry	C	1,395 ac	—	Recreation	Low
Buffalo Lake	Pierce	F	990 ac	1930	Fish and Wildlife Pond	Low
Beaver Lake	Logan	C	953.1 ac	1934	Recreation	Low
Green Lake	McIntosh	D	906 ac	1973	Recreation	Low
Belourt Outlet Lake	Rolette	D	827 ac	1930	Recreation	High
Belcourt Lake Beach	Rolette	F	827 ac	1930	Recreation	High
Nelson Lake	Oliver	D	660 ac	1967	Other	High
Lake Lamoure	LaMoure	C	494.1 ac	1973	Recreation	Significant
Mt Carmel Dam Lake	Cavalier	B	386 ac	1971	Recreation	Significant
Harvey Dam Lake	Wells	C	360 ac	1920	Water Supply	Significant
South Golden Lake	Steele	C	330 ac	1957	Recreation	Low
North Golden Lake	Steele	C	313 ac	1957	Recreation	Low
Homme Dam Lake	Walsh	B	290 ac	1950	Water Supply	High
Stanley Reservoir	Mountrail	D	253 ac	1968	Water Supply	Low
Bisbee-Big Coulee Dam Lake	Towner	C	240 ac	1968	Recreation	Significant
Indian Creek Dam Lake	Hettinger	C	236 ac	1979	Recreation	Significant
Larson Lake	Hettinger	C	235 ac	1934	Recreation	Low
Pheasant Lake	Dickey	B	234 ac	1963	Water Supply	Significant
Renwick Dam Lake	Pembina	C	223 ac	1962	Flood Risk Reduction	High
Cedar Lake	Slope	F	210 ac	1935	Fish and Wildlife Pond	Low
Fordville Dam Lake	Grand Forks	C	197.1 ac	1978	Flood Risk Reduction	High
Froelich Dam Lake	Sioux	D	175 ac	1962	Recreation	Low
Tolna Dam Lake	Nelson	D	166.3 ac	1936	Recreation	Significant
Gordon Center Lake	Rolette	B	164 ac	1960	Recreation	High
Wheaton Lake	Rolette	B	164 ac	1960	Recreation	High
Gordon Beach Lake	Rolette	F	164 ac	1960	Recreation	High
Wheaton Beach Lake	Rolette	C	164 ac	1960	Recreation	High
White Earth Dam Lake	Mountrail	C	160.2 ac	1970	Recreation	High
Blacktail Dam Lake	Williams	B	158 ac	1959	Recreation	Significant
Northgate Dam Lake	Burke	B	152 ac	1968	Recreation	Significant
Epping-Springbrook Dam-Deepest Lake	Williams	D	148 ac	1935	Recreation	Significant
Harmon Lake	Morton	F	144 ac	2007	Recreation	Significant
Whitman Dam Lake	Nelson	B	143.4 ac	1965	Flood Risk Reduction	Significant
Hiddenwood Lake	Ward	C	131 ac	1933	Flood Risk Reduction	Low
Brewer Lake	Cass	D	130 ac	1970	Recreation	Significant
Odland Dam Lake	Golden Valley	D	128.2 ac	1936	Recreation	Low
Silver Lake	Sargent	C	124 ac	1937	Recreation	Low
Dead Colt Creek Dam Lake	Ransom	F	124 ac	1984	Flood Risk Reduction	Significant
Short Creek Dam Lake	Burke	C	112 ac	1962	Recreation	Significant
Lake Upsilon	Rolette	A	110 ac	1966	Recreation	Low
Mirror Lake	Adams	F	94.33 ac	1909	Recreation	Significant
Sheep Creek Dam Lake	Grant	D	87 ac	1969	Recreation	Low
Tioga Dam Lake	Williams	D	82.5 ac	1963	Recreation	High
Armourdale Dam Lake	Towner	C	79.8 ac	1961	Fish and Wildlife Pond	Significant
Larimore Dam Lake	Grand Forks	D	72 ac	1979	Flood Risk Reduction	High
Bylin Dam Lake	Walsh	C	59.9 ac	1964	Flood Risk Reduction	High
Mcdowell Dam Lake	Burleigh	D	59.5 ac	1976	Recreation	Significant
Sprague Lake	Sargent	F	58 ac	1965	Fish and Wildlife Pond	Low
Warsing Dam Lake	Eddy	D	51 ac	1961	Recreation	Low
North Lemmon Lake	Adams	B	49.8 ac	1908	Fish and Wildlife Pond	Significant
Harmony Lake	Mercer	C	44.9 ac	1998	Recreation	Low
East Arroda Lake	Oliver	C	43.4 ac	1971	Recreation	Significant
Arroda Lake	Oliver	B	43.4 ac	1971	Recreation	Significant
Clausen Springs Lake	Barnes	C	42.7 ac	1967	Recreation	High
Baukol-Noonan Dam Lake	Divide	B	38 ac	1986	Recreation	Low
Mcleod Reservoir	Williams	C	38 ac	1890	Recreation	Low
Mcville Dam Lake	Nelson	C	33.4 ac	1910	Water Supply	Significant
Nygren Dam Lake	Morton	D	33.1 ac	1967	Recreation	Low
Moores Lake	Dickey	B	29.2 ac	1949	Recreation	Low
Kota Ray Dam Lake	Williams	B	27.7 ac	1933	Recreation	Low
Kulm-Edgeley Dam Lake	LaMoure	C	27 ac	1968	Recreation	Low
Arnegard Dam Lake	McKenzie	A	24.2 ac	1935	Recreation	Low
Balta Dam Lake	Pierce	C	18 ac	1937	Recreation	Low
Niagara Dam Lake	Grand Forks	F	16 ac	1935	Recreation	Low
Carlson-Tande Dam Lake	Griggs	C	15.79 ac	1967	Recreation	Low
Davis Dam Lake	Slope	B	15.3 ac	1963	Recreation	Low
Castle Rock Dam Lake	Hettinger	D	14.2 ac	1969	Recreation	Low
Custer Mine Pond	McLean	C	10.7 ac	1986	Fish and Wildlife Pond	Low
Kolding Dam Lake	Grand Forks	F	9.8 ac	1972	Flood Risk Reduction	Significant
Belfield Dam Lake	Stark	C	8.9 ac	1910	Recreation	Significant
Hurdsfield-Tuffy Lake	Wells	C	7 ac	1968	Recreation	Low
Velva Sportsmans Dam Lake	Ward	B	6.2 ac	1967	Recreation	Low
Kalina Dam Lake	Bowman	C	—	1940	Recreation	Low
Gascoyne Lake	Bowman	D	—	1934	Recreation	Low

Frequently Asked Questions

How many reservoirs are in Wisconsin?

93 of 158 graded Wisconsin lakes (59%) are man-made reservoirs in the USACE National Inventory of Dams. 55 are rated High or Significant hazard, meaning failure would put downstream lives or property at substantial risk. The oldest matched dam dates to 1890.

What's the largest reservoir in Wisconsin?

The largest matched reservoir in Wisconsin is Devils Lake in Ramsey County at 140,000 acres of normal surface area, impounded by the Spirit Lake Jetty 1 (completed 1997).

What's the difference between a reservoir and a natural lake?

A reservoir is a body of water impounded by a man-made dam — typically built for flood control, hydroelectric power, water supply, irrigation, or recreation. A natural lake formed without human intervention, usually from glacial scouring, volcanic activity, or river meandering. Reservoirs typically have shoreline that fluctuates with seasonal water level management, while natural lakes have more stable shorelines. The USACE National Inventory of Dams classifies every regulated dam in the United States, which is how we identify which LakeGrade lakes are actually reservoirs.

What does the hazard class mean?

USACE assigns each dam a hazard potential classification based on what would happen downstream if the dam failed — NOT how likely the dam is to fail. "Low" hazard means dam failure would cause no probable loss of life and only low economic loss. "Significant" means probable loss of life is unlikely but appreciable economic damage would occur. "High" means probable loss of life and significant economic damage. The classification is about consequence, not condition. Many High-hazard dams are perfectly safe; they're rated High because populated areas have grown downstream over time.

Where does this reservoir data come from?

Every reservoir record on this page is matched to the USACE National Inventory of Dams (NID), the federal database of all dams ≥25 ft tall or impounding ≥50 acre-feet, plus any dam that poses a Significant or High hazard regardless of size. The NID is published by the U.S. Army Corps of Engineers and updated annually. Surface area, storage capacity, dam height, and hazard classification come directly from NID records.

Data source

Reservoir data from the USACE National Inventory of Dams (NID), the federal database of all regulated dams. Dam attributes (height, year completed, storage capacity, hazard class) are matched to LakeGrade lakes by proximity and dam-name similarity. Some lakes may be reservoirs that aren't matched if the dam record uses a name substantially different from our lake name.