Avalon is the only incorporated city on Santa Catalina Island, in the California Channel Islands, and the southernmost city in Los Angeles County. The city is a resort community with the waterfront dominated by tourism-oriented businesses. The older parts of the town on the valley floor consist primarily of small houses and two and three-story buildings in various traditional architectural styles.

Santa Catalina Island is a rocky island off the coast of Southern California in the Gulf of Santa Catalina. The island covers an area of about 75 square miles. It features a diverse and rugged landscape, including rolling hills, canyons, coastal cliffs, and sandy beaches. The island's highest peak is Mount Orizaba, rising to an elevation of 2,097 feet. The island is 22 mi long and 8 mi across at its largest width. The island is situated in the Pacific Ocean, approximately 29 mi south-southwest of Long Beach, California. Politically, Catalina Island is part of Los Angeles County in District 4. Most of the island's land is unincorporated and is thus governed by the county.