Before the arrival of Europeans, San Nicolas Island was inhabited by the little-known Nicoleno people, distinct from the Chumash who lived elsewhere in the Channel Islands chain and along the coast.

More than 530 archaeological sites exist on the island, some more than 7,000 years old. The Nicoleno, who survived on shellfish and sea mammals, lived in homes made of whale ribs with seal skins stretched over them, said Steve Schwartz, an archaeologist on the island.

The islanders were renowned for their whale, seal and fish sculptures in stone. Archaeologists have also found intricate fish hooks, harpoons and woven baskets.

"We have had archaeological work going on here since the 1870s," Schwartz said. "If you go around the world, you'll find artifacts from San Nicolas Island in museums."

In 1835, Spanish missionaries decided to remove the Indians from the island. But one was mistakenly left behind, a 12-year-old girl who lived alone for 18 years. Her story was told in author Scott O'Dell's bestseller, "Island of the Blue Dolphins." She was rescued in 1853 and taken to Santa Barbara, where she died of disease a few weeks later, Schwartz said.

During World War II, San Nicolas was primarily a lookout post to guard against Japanese ships and submarines. After the war, it became a missile test center.

San Clemente Island, near San Diego, became a bombardment range.

Neither island is part of Channel Islands National Park.