Green Island is a small volcanic island in the Pacific Ocean about 33 km (21 mi) off the eastern coast of Taiwan. It is 15.092 km² (5.83 sq mi) at high tide and 17.329 km² (6.69 sq mi) at low tide, making it the Republic of China's fourth-largest island. The island is administered as Lüdao Township, a rural township of Taitung County and one of the county's two offshore areas (the other being Orchid Island).