琼州海峡
Hainan, separated by the wide Qiongzhou Strait from the Leizhou Peninsula of Guangdong, is the largest island administered by the People's Republic of China and the 42nd largest in the world. The area of Hainan Island (, 97% of the province) is similar to that of Belgium or slightly smaller than that of Taiwan. To the west of Hainan Island is the Gulf of Tonkin. Wuzhi Mountain is the highest mountain on the island at .