Lakes / Missouri / St. Charles County / Grassy Lake
Grassy Lake, St. Charles County, Missouri
51.15 acres
Surface Area
Where It Sits, and How Deep It Goes
Locator - Missouri
38.87 degrees N, 90.71 degrees W - St. Charles 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 Grassy Lake Stacks Up
- Larger than 48% of the 352 lakes counted in Missouri.
- About 33 miles from St. Louis, as the crow flies.
Lakes Nearby
| Lake | County | Distance | Surface Area |
|---|---|---|---|
| Lharky Lake | St. Charles | 0.4 mi | 58.07 acres |
| Mud Lake | St. Charles | 0.6 mi | 77.1 acres |
| Horseshoe Lake | St. Charles | 1.9 mi | 82.53 acres |
| Horseshoe Lake | St. Charles | 3.5 mi | 51.65 acres |
| Lake Saint Louis | St. Charles | 6.5 mi | 444.3 acres |
| Lake Saint Louise | St. Charles | 6.9 mi | 71.41 acres |
Straight-line distance between lake centers.
Facts and Figures
Questions About Grassy Lake
How Big Is Grassy Lake?
Grassy Lake covers 51.15 acres in St. Charles County, Missouri.
What Is the Largest Lake in St. Charles County?
Lake Saint Louis is the largest lake in St. Charles County, at 444.3 acres.
Largest Lakes in Missouri
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | Lake of the Ozarks | Camden | 51,171.75 acres | - |
| 2 | Harry S Truman Reservoir | Benton | 49,365.93 acres | - |
| 3 | Table Rock Lake | Stone | 41,777.86 acres | - |
| 4 | Stockton Lake | Cedar | 24,962.34 acres | - |
| 5 | Mark Twain Lake | Ralls | 18,362.33 acres | - |
All 352 Missouri lakes ranked by surface area
Sources: USGS National Hydrography Dataset (The National Map) lake data (ID 105761846). Verified October 30, 2026.