| Neils Island | |
| Image Alt: | Aerial image of an island. |
| Pushpin Map: | United States San Francisco Bay Area#USA California#USA |
| Coordinates: | 38.1908°N -122.5781°W |
| Location: | Northern California |
| Waterbody: | Petaluma River |
| Area Sqft: | or |
| Area Acre: | --> |
| Length Ft: | --> |
| Width Ft: | --> |
| Coastline Ft: | --> |
| Elevation Ft: | 82 |
| Country: | United States |
| Country Admin Divisions Title: | State |
| Country Admin Divisions Title 1: | County |
| Country Admin Divisions 1: | Sonoma |
Neils Island (sometimes called Neil Island) is a former island in Sonoma County, California, close to (and formerly surrounded by wetlands of) the Petaluma River, upstream of San Pablo Bay (an embayment of San Francisco Bay). Its coordinates are 38.1908°N -122.5781°W, and the United States Geological Survey measured its elevation as in 1981. It appears in a 1954 USGS map of the region.