Lakes / Pennsylvania / Mcwilliams Reservoir
Mcwilliams Reservoir, Pennsylvania
183 acres
Surface Area
1,062 ft
Surface Elevation
Where It Sits, and How Deep It Goes
Locator - Pennsylvania
40.83 degrees N, 76.41 degrees W - Columbia County. State and county outlines drawn from Census boundary data; the lake marker is placed by its Pennsylvania Fish and Boat Commission coordinates, not by eye. Schematic - not a survey map.
How Mcwilliams Reservoir Stacks Up
- The largest lake in Columbia County among those counted.
- About 46 miles from Harrisburg, as the crow flies.
Facts and Figures
Waterbody ID405000762514
CountyColumbia
Fishing IncludesLargemouth Bass, Bluegill, Pumpkinseed
Coordinates40.8336, -76.4106
Deepest Natural Lakes in Pennsylvania
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | Struble Lake | Chester | 146 acres | 19 ft |
Largest Lakes in Pennsylvania
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | Pymatuning Reservoir | Crawford | 13,920 acres | About 25 ft |
| 2 | Allegheny Reservoir | Warren | 12,081 acres | 128 ft |
| 3 | Raystown Lake | Huntingdon | 8,297 acres | None |
| 4 | Lake Wallenpaupack | Pike, Wayne | 5,698 acres | 60 ft |
| 5 | Shenango River Lake | Mercer | 3,559 acres | 30 ft |
Sources: Pennsylvania Fish and Boat Commission lake data (ID 405000762514); USGS; Pennsylvania Fish and Boat Commission, WWCW Fisheries Lakes (PASDA PAFishBoat layer 27). Verified October 28, 2026.