Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It is generally mountainous, about 274 km (170 mi) from north to south and at least 97 km (60 mi) wide. Its total area is 20,779 km2 (8,023 sq mi). Wales has over 1,200 km (746 mi) of coastline, including its offshore islands; the largest, Anglesey (Ynys Mon), is also the largest island in the Irish Sea. The highest mountains are in the north and central areas, especially in Snowdonia (Eryri), which contains Snowdon (Yr Wyddfa); at 1,085 m (3,560 ft), its highest peak.