Prachuap Khiri Khan covers an area of 6,367.62 square kilometres (2,458.55 sq mi). The district is located on the Kra Isthmus, the narrow landbridge connecting the Malay Peninsula with mainland Asia. The province contains the narrowest part of Thailand - directly south of the capital, it is just 13 km (8.1 mi) from the coast of the Gulf of Thailand to the border with Myanmar. The narrowest point of the isthmus, however, is further south in Chumphon Province. Geographically, Prachuap Khiri Khan is a moderate plain area with altitude varying from sea level to 1,200 m (3,900 ft) above sea level. The maximum altitude can be reached in the north eastern and central west regions, which makes up approximately 30% of the area.