Stewart Island lies below the southernmost bluff of South Island, from which it is separated by the deceptive Foveaux Strait. In shape it is an irregular isosceles triangle with a base extending north-west and south-east along the Foveaux Strait. Having an area of only 665 square miles it is by far the smallest of the three main islands of New Zealand. It is interesting to note that the forty-seventh parallel of latitude south passes through the middle of Stewart Island; the forty-seventh parallel north cuts Switzerland in half.