Kure Atoll is a nearly circular coral reef 10 km in diameter. Three islands originally emerged from the atoll: Green Island in the south, Sand Island in the mid of the eastern reef, and Core Island in the north. Sand Island is about 0.9 by 0.5 miles in area, and up to 9 ft high.Core Island has not been emergent for years. Green Island is about 1.5 miles in length (oriented northeast to southwest) and is about 0.75 miles wide. The highest elevation on Kure (about 20 ft.) is found here. The island is composed of sand and coral. There is one house and minor remains of the Loran station that was decommissioned in 1992. A 4000-ft. airstrip, formerly used infrequently by the coastguard and by scientific workers, is now unuseable.