Cuarteron Reef, also known as Calderon Reef (Mandarin Chinese: 華陽礁/华阳礁; pinyin: Huáyáng Jiāo; Filipino: Bahura ng Calderon; Vietnamese: Đá Châu Viên; Malay: Terumbu Kalderon), is a reef at the east end of the London Reefs in the Spratly Islands of the South China Sea. It is occupied and controlled by China (PRC) (as part of Sansha), and also claimed by the Philippines (as part of Kalayaan), by Vietnam (as part of Truong Sa) and Taiwan (ROC). The reef is 3 nautical miles (5.6 km; 3.5 mi) long and has an area of 8 square kilometres (3.1 sq mi) (800 hectares (2,000 acres)).