evidence: Hainan, sheng (province) in southern China. Its name means "south of the sea." The main land territory of the province is coextensive with Hainan Island and a handful of nearby offshore islands located in the South China Sea and separated from the Leizhou Peninsula of southern Guangdong province to the north by the shallow and narrow Hainan Strait (Qiongzhou Haixia). The west coast of Hainan Island is some 200 miles (320 km) east of northern Vietnam, across the Gulf of Tonkin. [...] Hainan is the southernmost province of China and is also the smallest in terms of land area. For centuries Hainan was part of Guangdong province, but in 1988 this resource-rich tropical region became a separate province. The capital is Haikou, on Hainan Island’s northern coast. Area (excluding disputed island areas) 13,200 square miles (34,300 square km). Pop. (2020) 10,081,232. Hainan Island was geologically connected with the southern Chinese mainland until a rift through the Hainan Strait opened sometime during the Miocene and Pliocene epochs (about 23 to 2.6 million years ago). The island is approximately oval in shape and measures about 160 miles (260 km) from east to west and 130 miles (210 km) from north to south at its widest point. The land rises abruptly in the southwestern interior of the island, reaching an elevation of 6,125 feet (1,867 metres) above sea level at Mount Wuzhi. Immediately to the northwest of the Wuzhi massif is the Limu Range, with several peaks above 4,600 feet (1,400 metres).