Decoto is a neighborhood of Union City, California originally established as a separate community. It is located north-northwest of downtown Newark,
In 1958, Decoto joined Alvarado to form Union City.
United Airlines Flight 615 crashed near Decoto on its approach to Oakland airport shortly before 4:30 AM Pacific Time on August 24, 1951.
Today the growth of the adjacent Transit District is leading to rapid changes in demographics.