SR 1 splits from US 101 at Santa Rosa Street in San Luis Obispo and then resumes as a four lane road as the Cabrillo Highway. It rejoins the coast in Morro Bay, running through that city as a freeway, where it crosses Morro Creek at the site of a prehistoric Chumash settlement dating to the Millingstone Horizon. From there, SR 1 proceeds north to Cayucos until it again becomes a winding, two lane road with occasional passing lanes. It then continues along the coast through Cambria and San Simeon, and past the elephant seal colony at Piedras Blancas Light Station. SR 1 provides access to Hearst Castle in San Simeon in Northern San Luis Obispo County.