Lakes / California / San Diego County / Lake O'Neill
Lake O'Neill, California
97 acres
Surface Area
Where It Sits, and How Deep It Goes
Locator - California
33.33 degrees N, 117.32 degrees W - San Diego 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 O'Neill Stacks Up
- Larger than 54% of the 1,147 lakes counted in California.
- About 43 miles from San Diego, as the crow flies.
Lakes Nearby
| Lake | County | Distance | Surface Area |
|---|---|---|---|
| Windmill Lake | San Diego | 5.4 mi | 29 acres |
| Whelan Lake | San Diego | 6.0 mi | 29 acres |
| Guajome Lake | San Diego | 6.4 mi | 25 acres |
| Lake San Marcos | San Diego | 16 mi | 56 acres |
| Turner Lake | San Diego | 16 mi | 37 acres |
| Dixon Reservoir | San Diego | 20 mi | 63 acres |
Straight-line distance between lake centers.
Facts and Figures
Questions About Lake O'Neill
How Big Is Lake O'Neill?
Lake O'Neill covers 97 acres in San Diego County, California.
What Is the Largest Lake in San Diego County?
Lake Henshaw is the largest lake in San Diego County, at 1,754 acres.
Largest Lakes in California
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | Salton Sea | Imperial | 233,096 acres | - |
| 2 | Lake Tahoe | Placer | 122,975 acres | - |
| 3 | Goose Lake | Modoc | 93,048 acres | - |
| 4 | Honey Lake | Lassen | 59,917 acres | - |
| 5 | Mono Lake | Mono | 45,124 acres | - |
All 1,147 California lakes ranked by surface area
Sources: USGS NHD (The National Map NHD MapServer layer 12) named waterbodies FTYPE 390/436; counties via Census point-in-polygon lake data (ID 27598329). Verified October 30, 2026.