| Green Island | |
| Image Alt: | Aerial image of an island. |
| Pushpin Map: | United States San Francisco Bay Area#USA California#USA |
| Coordinates: | 38.2025°N -122.3044°W |
| Location: | Northern California |
| Waterbody: | Napa River |
| Area Sqft: | or |
| Area Acre: | --> |
| Length Ft: | --> |
| Width Ft: | --> |
| Coastline Ft: | --> |
| Elevation Ft: | 23 |
| Country: | United States |
| Country Admin Divisions Title: | State |
| Country Admin Divisions Title 1: | County |
| Country Admin Divisions 1: | Napa |
Green Island is an island in the Napa River, upstream of San Pablo Bay (an embayment of San Francisco Bay). It is in Napa County, California, and managed as part of the Napa-Sonoma Marshes Wildlife Area. Its coordinates are 38.2025°N -122.3044°W, and the United States Geological Survey measured its elevation as in 1981. It, long with Island No. 1, Island No. 2 and Tubbs Island, are labeled on a 1902 USGS map of the area.