European settlement of Refugio Valley first, briefly, was for agriculture. From 1878 the main production facilities of California Powder Works occupied the lower Refugio Valley; to the southeast in the upper Valley were small storage and shipping facilities.
When the era of explosives manufacture ended, the upper Valley was subdivided and sold as residential lots beginning in 1972.
Later, beginning in 2001, residential development occured in the lower Refugio Valley as economic values and new construction techniques overcame geologic and hydrologic challenges.
Transportation was vital. Barges loaded dynamite at a wharf built a half-mile east of Hercules Station; another “Acid Wharf”, extending from the small point of land jutting into the bay, handled feedstocks and general freight. In 1899, a second railroad arrived a mile up the valley, providing competition for rail
shipments.
Pinole, with two passenger railroad stations, was also the gateway for travel to the larger cities of the Bay Area. San Pablo Avenue, the 1865 stage road connecting the two towns, followed the hills south to Oakland and east towards Sacramento.It was designated in 1927 a segment of United States Route 40, the Lincoln Highway, the first transcontinental improved road. In 1959, Interstate Highway 80 was constructed through the hills on a route parallel to US 40, bisecting the Hercules Works property.
