2018 Map of Union Island

About this map

Union Island and the surrounding delta lowlands of the San Joaquin Valley define this modern landscape of engineered waterways and agricultural tracts. Situated between the growing cities of Tracy and Lathrop, the area is a network of managed watercourses including the Grant Line Canal, Fabian and Bell Canal, and several natural sloughs. The map illustrates how human development has adapted to the Sacramento-San Joaquin River Delta, with levees such as S Wing Levee Rd and drainage features like Paradise Cut and Sugar Cut protecting the fertile island soils. While the southern portion near Tracy shows industrial and residential expansion along Byron Rd and W Grant Line Rd, the north remains largely defined by the agricultural geometry of Union Island and Roberts Island, reflecting the long-standing importance of this region to California's agricultural economy.