Eleven miles north of Florence, Highway 101 runs along a headland three hundred feet above the Pacific, and underneath it is the largest sea cave in the United States. The main chamber covers about two acres beneath a vaulted rock dome roughly 125 feet high, and the ocean washes into it without pause. A low passage runs a thousand feet south to a second opening, flooded at high tide and walkable at low. Measured at 1,315 feet, it ranks around tenth among the world's longest sea caves and first in the country, ahead of the undeveloped Painted Cave on Santa Cruz Island.
The walls are not grey. Lichens, algae and mineral staining have coloured them green, pink, purple, buff and red, and generations of guides have named the shapes: Lincoln's Head, the Indian Maiden, the Goddess of Liberty.
Biologically, it is the only known mainland rookery and wintering haul out of the Steller sea lion, with California sea lions using it to a lesser extent. Steller sea lions are the largest of the eared seals, and hearing several hundred of them in an enclosed stone room is not a quiet experience. The high vault above the water is a seabird roost as well, holding pigeon guillemots, Brandt's cormorants, western, herring and California gulls, tufted puffins, and the occasional hawk or bald eagle.
The cave was found in 1880 by a local seaman, and access today is by elevator down through the rock from the gift shop on the highway. Whether the animals are inside the cave or out on the rocks depends on the season and the weather: they tend to be in the cave through autumn and winter and out on the ledges in spring and summer. The whale watching deck below the shop looks about twenty miles out to sea, and grey whales pass close enough to see from it for much of the year.
Other places on the map within a couple of hours.
