The country's islands lie between latitudes 5° and 13°S, and longitudes 155° and 169°E. The distance between the westernmost and easternmost islands is about . The Santa Cruz Islands (of which Tikopia is part) are situated north of Vanuatu and are especially isolated at more than  from the other islands. Bougainville is geographically part of the Solomon Islands archipelago but politically part of Papua New Guinea.