Lakes / South Dakota / Sully County / Post Lake
Post Lake, South Dakota
35.35 acres
Surface Area
Where It Sits, and How Deep It Goes
Locator - South Dakota
44.63 degrees N, 99.91 degrees W - Sully 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 Post Lake Stacks Up
- Larger than 8% of the 533 lakes counted in South Dakota.
- About 28 miles from Pierre, as the crow flies.
Lakes Nearby
| Lake | County | Distance | Surface Area |
|---|---|---|---|
| Durrstein Lake | Sully | 7.8 mi | 83.68 acres |
| Walker Lake | Sully | 10 mi | 59.59 acres |
| Woodruff Lake | Hughes | 11 mi | 85.91 acres |
| Cottonwood Lake | Sully | 15 mi | 461.59 acres |
| Sully Lake | Sully | 15 mi | 212.26 acres |
| Warnes Slough | Sully | 16 mi | 364.97 acres |
Straight-line distance between lake centers.
Facts and Figures
Questions About Post Lake
How Big Is Post Lake?
Post Lake covers 35.35 acres in Sully County, South Dakota.
What Is the Largest Lake in Sully County?
Stone Lake is the largest lake in Sully County, at 1,023.51 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 144112124). Verified October 30, 2026.