Lakes / California / Contra Costa County / Mallard Reservoir
Mallard Reservoir, California
203 acres
Surface Area
Where It Sits, and How Deep It Goes
Locator - California
38.02 degrees N, 122.04 degrees W - Contra Costa 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 Mallard Reservoir Stacks Up
- Larger than 69% of the 1,147 lakes counted in California.
- About 27 miles from San Francisco, as the crow flies.
Lakes Nearby
| Lake | County | Distance | Surface Area |
|---|---|---|---|
| Lake Herman | Solano | 8.2 mi | 96 acres |
| Briones Reservoir | Contra Costa | 11 mi | 669 acres |
| Lafayette Reservoir | Contra Costa | 11 mi | 105 acres |
| Contra Loma Reservoir | Contra Costa | 12 mi | 69 acres |
| San Pablo Reservoir | Contra Costa | 13 mi | 785 acres |
| Antioch Municipal Reservoir | Contra Costa | 13 mi | 57 acres |
Straight-line distance between lake centers.
Facts and Figures
Questions About Mallard Reservoir
How Big Is Mallard Reservoir?
Mallard Reservoir covers 203 acres in Contra Costa County, California.
What Is the Largest Lake in Contra Costa County?
Clifton Court Forebay is the largest lake in Contra Costa County, at 2,215 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 43055267). Verified October 30, 2026.