Largest Lakes in South Dakota
1 South Dakota lakes with measured surface area, ranked by acreage. The biggest lake in South Dakota is Canyon Lake, which tops the list at 29 acres in Pennington County.
Reading South Dakota's size profile
South Dakota's largest lake by surface area is Canyon Lake in Pennington County, spanning 29 acres. Most of South Dakota's biggest waters are reservoirs — dammed river valleys built for water supply, flood control, and recreation, so their footprints shift with pool level.
Surface area is a poor proxy for water quality on its own — a large lake can hold a clean, deep core and a nutrient-loaded bay at the same time. Each lake below links to its full report card with grade, clarity, depth, and EPA impairment status. Area figures come from state DNR surveys and the USACE National Inventory of Dams; grades come from EPA and state monitoring data.
The 1 biggest lakes in South Dakota by surface area
| # | Lake | County | Surface area | Max depth | Grade |
|---|---|---|---|---|---|
| 1 | Canyon Lake | Pennington | 29 acres | - | A |
Frequently Asked Questions
What is the largest lake in South Dakota?
The largest lake in South Dakota in the LakeGrade dataset is Canyon Lake in Pennington County at 29 acres. Water quality grade: A.
How is lake surface area measured?
Surface area comes from state DNR lake surveys and, for reservoirs, US Army Corps of Engineers (USACE) National Inventory of Dams records. Area is reported in acres at normal pool level. Reservoirs rise and fall with management and drought, so their listed area is the long-term normal rather than a single-day reading.
Are South Dakota's largest lakes natural or reservoirs?
Of the top 1 South Dakota lakes by area, 1 sit on a dammed river (reservoirs) and 0 are natural basins. Glacial states (MN, WI, MI, NY) skew natural; plains and southern states (MO, IA, ND, OH) skew toward reservoirs built for water supply, flood control, and recreation.
Do larger lakes have better water quality?
Not reliably. Quality varies more within a big lake than between lakes — a large lake can have a clean, deep main basin and a murky, algae-prone bay fed by a tributary, so one grade can mask wide swings. Depth, watershed land use, and how fast the lake flushes matter far more than raw surface area.
How big is the typical South Dakota lake in this ranking?
Across the top 1 South Dakota lakes by surface area, the median is 29 acres (Canyon Lake). This list is biased toward the biggest waters; the typical South Dakota lake is far smaller.
Where to stay near South Dakota's largest lakes
Planning a trip? Jump to live cabin, resort, and hotel availability near South Dakota's biggest lakes.