Andrew Molera State Park was once part of the Mexican land grant Rancho El Sur. Although the grant was made in 1834 to Juan Bautista Alvarado, who later became governor of the province, it was soon acquired by his uncle, J.B.R. Cooper, a Monterey sea captain and merchant who came to California in 1823. Beginning in 1834, Cooper had a number of buildings constructed on the ranch. Cooper Cabin, built in the spring of 1861, is the oldest surviving ranch structure and the oldest building on the Big Sur Coast. Its actual builder was George Austin, a Massachusetts native who worked for Cooper in various capacities, and on February 23, 1861, the two signed a contract for Austin to build a three-room block house. Tree-ring analysis later verified the construction date by showing that the cabin’s logs were cut in the spring of 1861. The cabin was built of broad-axed and adzed redwood logs and covered with hand-split redwood shingles. Austin’s Massachusetts background is reflected in the cabin’s lap-jointed and pegged corners, a building technique common in New England but virtually unknown west of the Rockies. The structure originally served as a dwelling for Cooper’s ranch hands, who worked in stockraising and dairying. The ranch supplied cattle and horses for Cooper’s other land holdings and produced beef and cheese for sale in Monterey. The cabin has been modified only slightly over the years: the wood floor in the central room was added later, the doors and windows are recent restorations, most of the current shakes are replacements, and the large opening on the southwest end dates from sometime after the 1930s, when the building was used as a barn.