Lakes / South Dakota / Brookings County / Lake Sinai
Lake Sinai, South Dakota
1,789.59 acres
Surface Area
Where It Sits, and How Deep It Goes
Locator - South Dakota
44.27 degrees N, 97.08 degrees W - Brookings 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 Lake Sinai Stacks Up
- Larger than 93% of the 533 lakes counted in South Dakota.
- The largest lake in Brookings County among those counted.
- About 44 miles from Watertown, as the crow flies.
Lakes Nearby
| Lake | County | Distance | Surface Area |
|---|---|---|---|
| Twin Lakes | Kingsbury | 4.3 mi | 317.23 acres |
| Brush Lake | Brookings | 4.3 mi | 200.65 acres |
| Nelson Slough | Brookings | 4.4 mi | 70.43 acres |
| East Lake Badus | Lake | 5.3 mi | 138.87 acres |
| Molumby Slough | Lake | 6.2 mi | 201.89 acres |
| Pederson Slough | Brookings | 6.7 mi | 48.68 acres |
Straight-line distance between lake centers.
Facts and Figures
Questions About Lake Sinai
How Big Is Lake Sinai?
Lake Sinai covers 1,789.59 acres in Brookings County, South Dakota.
What Is the Largest Lake in Brookings County?
Lake Sinai is the largest lake in Brookings County, at 1,789.59 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 126759915). Verified October 30, 2026.