In 1849, Colonel Jonathan D. Stevenson (from New York) bought the Rancho Los Medanos land grant, and laid out a town he called New York of the Pacific. By 1850, this venture failed. With the discovery of coal in the nearby town of Nortonville, California, the place became a port for coaling, and adopted the name Black Diamond, after the mining firm that built the Black Diamond Coal Mining Railroad from there to Nortonville. Because of the industrial potential of the site, a name change to Pittsburg was proposed in 1909.
The original town site fronts on the Sacramento/San Joaquin River Delta, reflecting its origins as a deep water channel river port. (As of January 1, 2007, state legislation [Assembly Bill 2324] enabled the city to manage its own riverfront for commercial development and subsequent port operations). Since the early 1900s, the city has grown inland to the south, then spread east and west along State Route 4, now a freeway carrying resident commuters to jobs in the San Francisco Bay-Oakland Region. In the process, the former town of Cornwall, California was absorbed. The city has enjoyed continued residential redevelopment growth near its northern boundary, as well as ongoing construction of major subdivisions in the southwest hills, including San Marco Villas.