After many ships, including the SS Northerner and a lighthouse tender with supplies to build the facility, were lost to the jagged rocks surrounding the 326 foot sea stack Sugar Loaf and Blunt’s Reef offshore of Cape Mendocino, the lighthouse with attendant buildings including a carpenter shop, an oil house, a barn and a two-story residence were built on 171 acres of remote rangeland.

On December 1, 1868, the light began sending a signal of one white flash every thirty seconds. The United States Coast Guard took control of the Cape Mendocino Lighthouse in 1939 when the United States Lighthouse Service merged with the Coast Guard. The lighthouse was a 43 foot iron tower, sixteen sided and double balconied, a twin to the lighthouse at Point Reyes but for the roof shape.  At 422 feet, the height of the light exceeded the 420 feet Makapuu Point Light, making it the highest focal plane of any lighthouse in the United States. The lens had been shipped in through Eureka, California and then overland to the remote location as it was too risky to ship it directly to the lighthouse. 

Also due to the remote location, lighthouse tenders serviced the facility. In 1881, three men being sent to the lighthouse were killed while attempting to land in a small boat from the tender Manzanita. New dwellings were built in 1908 for the keepers, some of whom raised cows or ponies for the Ferndale to Petrolia stage coach line. At least ten keepers served this lighthouse from 1869 to 1926