Bethel Island is an island and census-designated place in Contra Costa County, California, located in the Sacramento–San Joaquin Delta approximately six miles east of Antioch. The community describes itself as "the heart of the California Delta," reflecting both its geographic position and its identity as a recreation-oriented, water-centered place. At the 2020 census, Bethel Island reported a population of 2,131. The island's modern history is tied to recreation and boating. Once part of the Delta's agricultural landscape, with names reflecting its ranching and farming past, Bethel Island developed through the early and mid-20th century into a destination for boating and fishing. One of its earliest marinas, Remsburg Marina, was established in 1938, and today the island is home to more than a dozen marinas that serve both residents and visitors exploring the Delta's channels and sloughs. Bethel Island is governed as a Special Act District created by the California state legislature, known as the Bethel Island Municipal Improvement District, which provides local services for the island community within unincorporated Contra Costa County. The island is ringed by levees that protect it within the Delta's tidal waterways, and its streets and homes are laid out along canals and channels that give many properties direct boat access. The community attracts a mix of permanent residents — including a significant number of retirees — along with weekend boaters and second-home owners. Its relative affordability compared with the broader Bay Area, combined with its unique waterfront lifestyle, makes it a distinctive and sought-after niche within the region. Bethel Island appeals to boaters, anglers, retirees, and anyone seeking a quiet, water-centered way of life within reach of the Bay Area's larger cities.