The earliest maps indicate the island was referred to as "Merrill" and "Schoolcraft Island" at one time, but was then purchased or land granted to the Dr. Ryer family.  We've also seen a non-official map that indicated the use of Sutter for a short time possibly for part of Ryer Island.  Note that it is boardered by Steamboat Slough in the Sacramento Delta region, Miner's Slough and Cache Slough also called the Sacramento Deep Water channel.  Over the last 150 years, Ryer Island was the site of a school district, a railroad, a fish canning operation, many types of farming, recreational resorts, housing communities, stores and restaurants, and a small RV resort called Snug Harbor, which was named the "Best Small Park of California" in 2001 by the California Travel Park Association.  (Actually, Snug Harbor is technically a peninsula attached to Ryer Island and is not Ryer Island land itself)