Lakes / South Dakota / Day County / Long Lake
Long Lake, Day County, South Dakota
2,062.06 acres
Surface Area
Where It Sits, and How Deep It Goes
Locator - South Dakota
45.17 degrees N, 97.62 degrees W - Day County. State and county outlines drawn from Census boundary data; the lake marker is placed by its USGS National Hydrography Dataset coordinates, not by eye. Schematic - not a survey map.
How Long Lake Stacks Up
- Larger than 94% of the 533 lakes counted in South Dakota.
- About 31 miles from Watertown, as the crow flies.
Lakes Nearby
| Lake | County | Distance | Surface Area |
|---|---|---|---|
| Horseshoe Lake | Day | 2.2 mi | 607.13 acres |
| Swan Lake | Clark | 4.1 mi | 936.31 acres |
| Cottonwood Lake | Clark | 4.7 mi | 462.39 acres |
| Mud Lake | Day | 5.0 mi | 62.76 acres |
| Heggs Lake | Clark | 5.9 mi | 392.43 acres |
| Pepper Slough | Clark | 8.4 mi | 111.44 acres |
Straight-line distance between lake centers.
Facts and Figures
Questions About Long Lake
How Big Is Long Lake?
Long Lake covers 2,062.06 acres in Day County, South Dakota.
What Is the Largest Lake in Day County?
Bitter Lake is the largest lake in Day County, at 7,865.28 acres.
Largest Lakes in South Dakota
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | Lake Oahe | Dewey | 309,912.57 acres | - |
| 2 | Lake Francis Case | Charles Mix | 82,166.92 acres | - |
| 3 | Lake Sharpe | Hughes | 58,419.67 acres | - |
| 4 | Lewis and Clark Lake | Bon Homme | 25,141.99 acres | - |
| 5 | Lake Thompson | Kingsbury | 13,887.93 acres | - |
All 533 South Dakota lakes ranked by surface area
Sources: USGS National Hydrography Dataset (The National Map) lake data (ID 145094241). Verified October 30, 2026.