1978 Map of Union Island

About this map

Union Island is a complex landscape of reclaimed delta lands defined by an intricate network of levees, canals, and pumping stations in the late 1970s. The northern reaches are characterized by the Gas Field and schools like Delta Island Sch, while the southern portion transition into the growing outskirts of Tracy. This map captures the intersection of heavy hydraulic engineering and agriculture, where the Middle River and Old River navigate through the El Pescadero (Pico and Naglee) land grant. The presence of numerous Pumping Stations and specialized water features like the Industrial Waste Ponds and the Fabian and Bell Canal illustrates the intensive management required to maintain these low-lying tracts for industrial and residential use. From the Landing Strip on the island to the emerging neighborhoods like Larch Clover Park, the map documents a region in the midst of suburban expansion into traditional ranchlands.