Deer Isle Thorofare Light is a lighthouse on Penobscot Bay, Maine, marking the western end of the Deer Island Thorofare and Merchant Row, important passages through the islands between Deer Isle and Isle au Haut. Established in 1857, the station included the present square brick tower and a keeper’s house at a time when nearby granite quarries were becoming major suppliers for eastern public buildings, increasing the value of safe navigation. The light was staffed until automation in 1958; after the keeper’s house burned in 1959 and other buildings were removed, the tower remained. Since 1998, the property has been managed by Island Heritage Trust as a bird sanctuary, while both Deer Isle Thorofare Light and Mark Island Light remain in local use.