Morro Rock in Morro Bay, California is perhaps the bay's most notable feature. The rock is 581 feet working as a volcanic plug, just offshore of Morro Bay City. It is also at the entrance to the harbor. There is a causeway that connects the rock to the shore, thus the rock is more like an island, only reachable during low tide. The rock is considered part of Santa Lucia Range. It has been dated to 20 million years ago, and is part of the Nine Sisters volcanic belt.
Surrounding the rock is protected area as part of Morro Rock State Preserve. Though one can walk around the rock at low tide, climbing is strictly forbidden and can result in fines should one attempt it. California seeks to preserve the bird life and vegetation the rock has.
Between 1889 and 1969 before the preserve was formed the rock was quarried for materials to form a breakwater in Morro Bay and Port San Luis Harbor. By 1966 a new law in California began to change how the rock could be used, until finally in 1969 the Historical Society won and it was called landmark number 821, being preserved forever.