Lakes / South Dakota / Hamlin County / Lake Saint John
Lake Saint John, South Dakota
1,271.11 acres
Surface Area
Where It Sits, and How Deep It Goes
Locator - South Dakota
44.57 degrees N, 97.19 degrees W - Hamlin 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 Saint John Stacks Up
- Larger than 91% of the 533 lakes counted in South Dakota.
- About 23 miles from Watertown, as the crow flies.
Lakes Nearby
| Lake | County | Distance | Surface Area |
|---|---|---|---|
| Lake Mary | Hamlin | 1.4 mi | 190.52 acres |
| Lake Norden | Hamlin | 2.2 mi | 711.66 acres |
| Lake Albert | Kingsbury | 2.7 mi | 3,655.43 acres |
| Gertson Slough | Hamlin | 3.4 mi | 91.92 acres |
| Lake Poinsett | Hamlin | 5.6 mi | 9,794.52 acres |
| Lake Marsh | Hamlin | 6.3 mi | 3,025.76 acres |
Straight-line distance between lake centers.
Facts and Figures
Questions About Lake Saint John
How Big Is Lake Saint John?
Lake Saint John covers 1,271.11 acres in Hamlin County, South Dakota.
What Is the Largest Lake in Hamlin County?
Lake Poinsett is the largest lake in Hamlin County, at 9,794.52 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 147528606). Verified October 30, 2026.