Isleton is a city in Sacramento County, California, United States. The population was 794 at the 2020 census, down from 804 at the 2010 census. It is located on Andrus Island amid the slough wetlands of the Sacramento-San Joaquin River Delta, on the eastern edge of the Rio Vista Gas Field. The city has many preserved 19th-century era storefronts along its main street, some of which show distinct Chinese influences.