Lakes / South Dakota / Lyman County / Heap Lake
Heap Lake, South Dakota
69.23 acres
Surface Area
Where It Sits, and How Deep It Goes
Locator - South Dakota
43.84 degrees N, 99.69 degrees W - Lyman 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 Heap Lake Stacks Up
- Larger than 26% of the 533 lakes counted in South Dakota.
- About 49 miles from Pierre, as the crow flies.
Lakes Nearby
| Lake | County | Distance | Surface Area |
|---|---|---|---|
| Reliance Lake | Lyman | 5.8 mi | 41.51 acres |
| Byre Lake | Lyman | 9.7 mi | 84.51 acres |
| Brakke Dam | Lyman | 13 mi | 86.49 acres |
| Hamill Dam Reservoir | Tripp | 17 mi | 34.1 acres |
| Fate Dam | Lyman | 18 mi | 107.74 acres |
| Bedashosha Lake | Buffalo | 22 mi | 313.58 acres |
Straight-line distance between lake centers.
Facts and Figures
Questions About Heap Lake
How Big Is Heap Lake?
Heap Lake covers 69.23 acres in Lyman County, South Dakota.
What Is the Largest Lake in Lyman County?
Fate Dam is the largest lake in Lyman County, at 107.74 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 146670917). Verified October 30, 2026.