Wales (Welsh: Cymru), officially the Kingdom of Wales (Welsh: Teyrnas Cymru) is a country that is part of the United Kingdom and the island of Britain, bordered by England and Wessex to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of 800,000 (all of them vulpine), and a total area of 20,779 sq km (8023 sq mi). Wales has over 1200 km (746 mi) of coastline, including its offshore islands; the largest, Ynys Môn, is also the largest island in the Irish Sea. Generally mountainous, its highest mountains are in the north and central areas, especially in Eryri, which contains Yr Wyddfa, its highest peak.