Flint Island is located about 740 kilometers (400 nautical miles) northwest of Tahiti, 190 km (100 nautical miles) south-southeast of Vostok Island, and 220 km (120 nautical miles) southwest of Caroline Island. The island is about 2.5 miles (4.0 km) long and 0.5 miles (0.80 km) wide at its widest point (4.0 by 0.8 km). It has a land area of 1 mi² (3 km ²) and rises to a height of 25 feet (8 m) above sea level. The island is surrounded by a narrow fringing reef and with no safe anchorage landing is difficult.
Flint island was discovered by the Spanish expedition of Ferdinand Magellan on 4 February 1521, and charted as Tiburones (Sharks in Spanish) because of the many sharks that sailors fished in it. Together with Puka-Puka (named San Pablo) they were named Islas Infortunadas (Unfortunate Islands in Spanish). A now-discredited theory held that the island was named after Captain Keen, who visited in 1835, but an entry in Krusenstern's Hydrographie der grössern Ozeane, published in 1819, makes it clear the island already had this name. Flint Island was claimed under the 1856 U.S. Guano Act, but it was apparently never occupied.
It was leased by the British to Houlder Brothers and Co. of London who carried out guano digging in the central part of the island from 1875 to 1880 under field manager John T. Arundel. From 1881 John T. Arundel & Co. carried on the mining business. The excavated areas have since filled with brackish water, forming two or three small lagoons. Coconut palms were planted on the island by Arundel in 1881 and copra was produced until 1891. The island was leased in 1911 to S.R. Maxwell and Co., Ltd. who employed 30 men and one manager to harvest copra from the approximately 30,000 coconut palms.
On January 3, 1908 a total eclipse of the sun was observed on the island by an expedition from the Lick Observatory in California. The observation point on the island was determined to be at latitude.
- Maude, H.E. "Spanish discoveries in the Pacific" Journal of the Polynesian Society, Wellington, New Zealand, 1959, Volume 68, No. 4, p 291-293.
- The Lick Observatory-Crocker Expedition to Flint Island