In The Case of the Haunted Island, Oto-Via was a remote Pacific atoll in French OCeania. Located east of the Paumotu archipelago, it was about 200 miles south of Atuona and 700 miles from Tahiti. Oto-Via was an atoll about 40 miles in circumference. The lagoon was about 12 or 13 miles surrounded by a narrow strip of coral mostly no more than a quarter mile in width. Oto-Via was unusual in that there was no passage through the reef into the lagoon. Oto-Via had been inhabited by a group of Pacific islanders. At first there had been rumours of a "mad Englishman" on the island. Later, Captain Dupreve of the schooner Tarivo had reported that the atoll was abandoned amidst rumours that it was haunted. These strange circumstances led to an investigation by Biggles and Marcel which finally unearthed the murder of Captain David MacDonald of the freighter Belinda.
Oto-Via is a fictional location.