St. Peter’s Island (German: St. Petersinsel, French: Île de St-Pierre) is a peninsula and former island situated in Lake Bienne in the canton of Bern, Switzerland. It has a length of about 5 kilometres and a maximum width of 800 metres. Its highest point is 474 metres above sea level or 45 metres above lake level (429 m). It was formed in the last Ice Age (see Pleistocene), when the Rhône Glacier reached as far as the Jura mountains. It is a promontory of the Jolimont, above Erlach.