Espiritu Santo, known locally as Santo, is the largest island in the New Hebrides, is of irregular shape, and about 76 by 46 miles in dimensions. It consists of two widely different regions. The eastern half of the island, largely a plateau of raised coral limestone with a general elevation of 300 to 600 feet, culminates in Mt. Turi, 1760 feet. The western half of the island is mountainous, rising to 5566 feet at Santo Peak (Iaiiriiri) and 6195 feet at Mt. Tabwemasana. This part has a well-developed drainage system. The largest river, the Yora, rises near Santo Peak and flows northeastward to St. Phillip and St. James Bay, locally called Big Bay. The mountains are heavily forested, and trees include the valuable kauri pine. Sandalwood was once common, but this resource has been much reduced by cutting.
The southeast coast of Espiritu Santo and the adjacent islands of Aore and Malo constitute one of the more important regions of European settlement in the group. Along both shores of Segond Channel, which separates Aore from the larger island, there are almost continuous stretches of plantations, and on the mainland shore is the French administrative, commercial, and missionary center of Luganville. During the Second World War, Espiritu Santo was developed as a military base that included a large airfield in the northern part. The British government agency was formerly at Hog Harbor in the northeast part of the island, and British-owned coconut plantations and missions are located here and on St. Phillip and St. James Bay.