Edgerly 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°12′12″N 122°18′52″W / 38.20333°N 122.31444°W / 38.20333; -122.31444 (Edgerly Island), and the United States Geological Survey measured its elevation as 3 ft (0.91 m) in 1981.