Fencing is an integral part of cattle ranching, as cattle can be controlled and distributed around the ranch depending on range conditions. The range fencing on Santa Rosa Island is barbed wire on posts. The posts are a combination of new and old, ranging from older redwood split posts to more recent peeled poles and metal posts. Older posts were often reused, and occasionally a piece of driftwood or other scavenged materials made do. The fence lines on the island date back to the More era, with some lines depicted on the 1874 map of the island.

For more detailed historical information and citations, please refer to the Historic Resource Study: Island Legacies - A History of the Islands within Channel Islands National Park