Island No. 1
Island No. 1 is a partially submerged island in the Napa River, upstream of San Pablo Bay. It is in Napa and Solano County, California, and parts of it are managed as part of the Napa-Sonoma Marshes Wildlife Area. Its coordinates are, and the United States Geological Survey measured its elevation as in 1981. It, along with Island No. 2, Green Island and Tubbs Island, are labeled on a 1902 USGS map of the area.