- Located in Santa Barbara County.
- Fifty-four miles from Ventura; 38 miles from the nearest mainland (San Pedro); 24 miles from Santa Catalina Island.
- Approximately 1.5 miles wide by one mile long; one square mile; 639 acres.
- Average rainfall-12 inches.
- Tallest peak-Signal Peak, 634 ft.
- Home to 14 endemic plant species and subspecies that occur only on the Channel Islands. Forms of buckwheat, dudleya, cream cups, and chicory are found only on Santa Barbara Island.
- The endemic, threatened island night lizard occurs only on Santa Barbara, San Nicolas, and San Clemente Islands.
- The island's cliffs offer perfect nesting habitat for one of the world's largest breeding colonies of Scripps's murrelets, rare seabirds.
- Absence of freshwater led the Tongva and Chumash to use the island on a seasonal basis and as a stopover between Santa Catalina and San Nicolas Islands.