Sonora Island is one of the outer islands (without ferry service) of the Discovery Islands of British Columbia, Canada.
The island took its name from the 36 ft (10.97 m) Spanish schooner that explored the Pacific Northwest in 1775. The expedition consisted of two ships: the Santiago, commanded by Bruno de Heceta and the schooner Sonora (la Señora), commanded by his second in command, Lieutenant Juan Francisco de la Bodega y Quadra. After some loss of life, Hezeta decided to return to Mexico, but Bodega y Quadra refused to follow him without having completed the essential mission, which was to locate the Russians. He continued northward on the Sonora and got as far as what is now close to Sitka, Alaska, reaching 59˚ North Latitude on 15 August 1775. Failing to find any Russians, he returned southward. When returning he made sure that he landed once to claim the coast for Spain. This expedition made it clear to the Spanish that the Russians didn’t have a large presence in the Pacific Northwest. The vessel, its full name Nuestra Señora de Guadalupe (generally known as the Señora) with a crew of 16 was intended to perform coastal reconnaissance and mapping, and could make landfall in places the larger Santiago was unable to approach on its previous voyage; in this way, the expedition could officially lay claim to the lands north of Mexico it visited.