Lakes / Louisiana / St. Martin County / Grassy Lake
Grassy Lake, St. Martin County, Louisiana
1,241.45 acres
Surface Area
Where It Sits, and How Deep It Goes
Locator - Louisiana
29.78 degrees N, 91.11 degrees W - St. Martin County. State and county outlines drawn from Census boundary data; the lake marker is placed by its Louisiana Department of Wildlife and Fisheries coordinates, not by eye. Schematic - not a survey map.
How Grassy Lake Stacks Up
- Larger than 85% of the 664 lakes counted in Louisiana.
- About 47 miles from Baton Rouge, as the crow flies.
Lakes Nearby
| Lake | County | Distance | Surface Area |
|---|---|---|---|
| Lake Palourde | St. Martin | 4.2 mi | 10,809.86 acres |
| Lake Verret | Assumption | 7.8 mi | 15,076.76 acres |
| Bay Wallace | Terrebonne | 12 mi | 109.78 acres |
| Duck Lake | St. Martin | 12 mi | 1,175.34 acres |
| Bateman Lake | St. Mary | 12 mi | 260.72 acres |
| Lake Cocodrie | Terrebonne | 14 mi | 575.2 acres |
Straight-line distance between lake centers.
Facts and Figures
Questions About Grassy Lake
How Big Is Grassy Lake?
Grassy Lake covers 1,241.45 acres in St. Martin County, Louisiana.
What Is the Largest Lake in St. Martin County?
Lake Palourde is the largest lake in St. Martin County, at 10,809.86 acres.
Deepest Natural Lakes in Louisiana
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | False River | Pointe Coupee | 3,212 acres | 65 ft |
| 2 | Vernon Lake | Vernon | 6 acres | 53 ft |
| 3 | Lake Concordia | Concordia | 1,026 acres | 50 ft |
| 4 | Caney Creek Reservoir | Jackson | 4,738 acres | 43 ft |
| 5 | Lake Providence | East Carroll | 1,380 acres | 37 ft |
All 27 Louisiana lakes ranked by depth
Largest Lakes in Louisiana
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | Lake Pontchartrain | Jefferson | 407,803.25 acres | - |
| 2 | Toledo Bend Reservoir | Sabine | 181,600 acres | 110 ft |
| 3 | Lake Maurepas | Livingston | 58,308.4 acres | - |
| 4 | Sabine Lake | Cameron | 56,867.74 acres | - |
| 5 | White Lake | Vermilion | 55,913.91 acres | - |
All 664 Louisiana lakes ranked by surface area
Sources: USGS National Hydrography Dataset (The National Map) lake data (ID 147016312). Verified October 30, 2026.