In 1887, using stone quarried and collected on the island and bricks manufactured on the island, Caire constructed a brick-faced, rubble and concrete double warehouse in which to store wool and wine awaiting shipment. A small-gauge rail system had been laid from a point behind the residence to the end of the pier, passing the doors of the warehouse, where goods could be loaded or unloaded from long, wide flatcars and carts. Incoming goods could be either unloaded into the warehouse or loaded onto wagons behind the house for the three-mile trip to the Main Ranch. The railway system was eventually dismantled, the job being taken over by trucks. In 2000 the central brick wall and the roof of the warehouse were repaired by the National Park Service.

More Ranch Information
Prisoner's Harbor was the gateway to the Main Ranch in the island's central valley and the grazing and agricultural lands and out-ranches on the western portion of the island. Its facilities were of the utmost importance to the island's owners as the shipping facility, entry point for visitors, and warehouse location. By the 1860s a ranch had been established at Prisoner's Harbor. Today, the buildings, structures, and plantings that remain are part of Santa Cruz Island Ranching District, which is eligible for listing in the National Register of Historic Places.