| Napa Sonoma Marsh | |
|---|---|
 Aerial view of the southern end of the Napa River in the Napa Sonoma Marsh | |
  Napa Sonoma Marsh Location in California | |
| Location | San Francisco Bay Area, California, USA |
| Coordinates | 38°10′07″N 122°20′22″W / 38.16871°N 122.33946°W |
| Type | Marsh |
| Part of | San Pablo Bay, San Francisco Bay |
| Primary inflows | Sonoma Creek Napa River |
| Surface area | 48,000 acres (190 km2) |
| Sections/sub-basins | San Pablo Bay National Wildlife Refuge |
| Website | Official website |
The Napa Sonoma Marsh is a wetland at the northern edge of San Pablo Bay, which is a northern arm of the San Francisco Bay in California, United States. This marsh has an area of 48,000 acres (190 km2), of which 13,000 acres (53 km2) are abandoned salt evaporation ponds.[citation needed] The United States Government has designated 13,000 acres (53 km2) in the Napa Sonoma Marsh as the San Pablo Bay National Wildlife Refuge.[citation needed]