[2] It protects nationally significant natural, cultural, and historical resources in Central California's coastal and ocean waters and offers opportunities for research, community engagement, and education and outreach activities.

[3][7] Undersea features within its boundaries include Arguello Canyon, Rodriguez Seamount, and a portion of the Santa Lucia Bank.

[7] Ecological habitats found in the sanctuary include extensive kelp forests, rocky reefs, deep-water coral gardens, sandy beaches, coastal dunes, and wetlands, the latter serving as nursery grounds for numerous commercial fish species and important habitats for many threatened and endangered species.

[4][7][8] The meeting of warm and cold ocean waters in the sanctuary, upwellings from the California Current, geologic features like Rodriguez Seamount and Santa Lucia Bank, and important biogeographic ecotones in the sanctary create ecological habitats that support biological productivity.

Habitats, physical features, or prey attract many threatened or endangered species — such as black abalone, blue whales, leatherback sea turtles, and snowy plovers — to the sanctuary's waters.

Coastal, ocean-going communities of Native Americans have existed in the area since prehistoric times, with evidence of settlements dating back to at least ca.

[7] Coastal schooners and other small sailing ships transported cargo such as lumber and produce along the coast of North America through the waters of what is now the Chumash Heritage National Marine Sanctuary during the entire combined history of control of the area by the Spanish Empire, Mexico, and the United States.

[3] The oldest ocean-going steamship lost in the sanctuary's waters was the wooden sidewheel paddle steamer SS Yankee Blade, wrecked off Point Arguello in 1854 while carrying passengers, cargo, and gold from San Francisco, California, to Panama, during the California Gold Rush in one of the worst maritime disasters in the history of the United States West Coast.

[7] Representatives of the Chumash people began to advocate protection of the coastal and ocean waters of the Central California coast in the 1980s.

[2][10] In November 2021, NOAA's Office of National Marine Sanctuaries issued a notice of intent to begin the designation process for the sanctuary,[10] proposing an area of about 7,600 square miles (19,700 km2) of the Pacific Ocean and a shoreline that extended for 156 miles (251 km), including coastal landmarks significant to the Chumash people's heritage from Gaviota Creek north to Santa Rosa Creek near the town of Cambria in San Luis Obispo County.