Thousand Islands – Frontenac Arch is one of four ecoregions of the Mixedwood Plains. The Thousand Islands in the Saint Lawrence River have a distinctive flora and fauna and are a part of the biological corridor. The bedrock is mostly gneiss, granite and marble, more than a billion years old. The Frontenac terrain is the youngest of the Ontario portions of the arch, dated at 1.2 billion years old. These rocks were once part of a large mountain chain of the ancient supercontinent of Rodinia. There is also a meteor crater near Holleford, where the shield meets the limestone plains of southeastern Ontario. The area
Thousand Islands (Svalbard) Gerard Valck and Peter Schenk the Elder were the first to place a "great vague mass of islands stretching round the coast" south of Edgeøya. William Scoresby (1820) is thought to have been the first to label them with the popular name of "Thousand Islands", the name they retain to this day. Thousand Islands (Svalbard) Thousand Islands () is a group of small islands south of Edgeøya. They form part of the Svalbard archipelago. The group consists of over forty islands and islets, including Brotskjer, Kulstadholmane, Utsira, Tufsen, Kong Ludvigøyane, Bölscheøya, Hornøya, Tiholmane, Meinickeøyane, Sletteøya, Schareholmane, Skråholmen, Brækmoholmane, Tareloppa, Vindholmen,