Malden Island is located 241 nautical miles south of the equator, roughly 1400 miles south of Honolulu, Hawaii, and more than 4000 miles west of the coast of South America. The nearest land is uninhabited Starbuck Island, 108 miles to the southwest. The nearest inhabited place is Tongareva (Penhryn Island), 243 miles to the southwest. The nearest airport is on Kiritimati (Christmas Island), 365 miles to the northwest. Other nearby islands (all uninhabited) include Jarvis Island, 373 miles to the northwest, Vostok Island, 385 miles to the south-southeast, and Caroline (Millennium) Island, 460 miles to the southeast.
The island has roughly the shape of an equilateral triangle 8 km on a side, aligned with the southwest side running northwest to southeast. The west and south corners of the triangle are slightly truncated, shortening the north, east and southwest coasts to about 7 km, and adding shorter west and south coasts about 1-2 km in length. A large, mostly shallow, irregularly shaped lagoon, containing a number of small islets, fills the east central part of the island. The lagoon is entirely enclosed by land, but only by relatively narrow strips along its north and east sides. Most of the land area of the island lies to the south and west of the lagoon. The total area of the island is about 3930 ha.
The island is very low, no more than 10 m above sea level at its highest point. The highest elevations are found along a rim that closely follows the coastline. The interior forms a depression that is only a few meters above sea level in the western part and is below sea level (filled by the lagoon) in the east central part. Because of this topography, the ocean cannot be seen from much of the interior.
A continuous heavy surf falls all along the coast, forming a narrow white to gray sandy beach. Except on the west coast, where the white sandy beach is more extensive than elsewhere, a strip of dark gray coral rubble, forming a series of low ridges parallel to the coast, lies within the narrow beach, extending inward to the island rim.
Malden was discovered on 30 July 1825 (not 29 July, as incorrectly reported in some sources) by Captain George Anson (Lord) Byron (a cousin of the recently deceased poet). Byron, commanding the British warship HMS Blonde, was returning to London from a special mission to Honolulu to repatriate the remains of the young king and queen of Hawaii, who had died tragically of measles during a visit to Britain. The island was named for Lt. Charles Robert Malden, navigator of the Blonde, who sighted the island and briefly explored it. Andrew Bloxam, naturalist of the Blonde, and James Macrae, a botanist travelling for the Royal Horticultural Society, joined in exploring the island and recorded their observations.
At the time of its discovery, Malden was found to be unoccupied, but the remains of ruined temples and other structures indicated that the island had at one time been inhabited. At various times these remains have been speculatively attributed to "wrecked seamen", "the buccaneers", "the South American Incas", "early Chinese navigators", etc. In 1924 the Malden ruins were examined by an archaeologist from the Bishop Museum in Honolulu, K.P. Emory, who concluded that they were the creation of a small Polynesian population which had resided there for perhaps several generations some centuries earlier.
In the first half of the nineteenth century, during the heyday of American whaling in the central Pacific, Malden was visited on a number of occasions by American whalers.
Malden was claimed by the U.S. Guano Company under the Guano Act of 1856, which authorized citizens to take possession of uninhabited islands under the authority of the United States for the purpose of removing guano, a valuable agricultural fertilizer. Before the American company began operations, however, the island was occupied by an Australian company under British license. This company and its successors exploited the island continuously from the 1860s through 1927.
In 1956 the United Kingdom selected Malden as the "instrumentation site" for its first series of thermonuclear (H-bomb) weapons tests, based at Christmas Island. British propagandists insisted that Malden should not be called a "target island". Nevertheless, the bombing target marker was located at the south point of the island and three thermonuclear devices were detonated at high altitude a short distance offshore in 1957.
The United States continued to dispute British sovereignty over Malden until after the independence of Kiribati was granted in July 1979. On 20 September, representatives of the United States and Kiribati met on Tarawa Atoll in the Gilbert Islands, and signed a treaty of friendship between their two nations (commonly referred to as the Treaty of Tarawa of 1979) by which the United States recognized Kiribati's sovereignty over Malden and thirteen other islands in the Line and Phoenix groups. This treaty entered into force on 23 September 1983.
The main value of the island to Kiribati lies in the resources of the 200-miles Exclusive Economic Zone which surrounds it, particularly the rich tuna fisheries. Gypsum deposits on the island itself are extensive, but do not appear to be economically viable under forseeable market conditions, mainly due to cost of transportation. Some revenue has been realized from ecotourism; the World Discoverer, an adventure cruise ship operated by Society Expeditons, visited the island once or twice annually for several years in the mid-1990s.
Malden was reserved as a wildlife sanctuary and closed area, officially designated the Malden Island Wildlife Sanctuary, on 29 May 1975, under the 1975 Wildlife Conservation Ordinance. The principal purpose of this reservation was to protect the large breeding populations of seabirds. The sanctuary is administered by the Wildlife Conservation Unit of the Ministry of Line and Phoenix Development, headquartered on Kiritimati. There is no resident staff at Malden, and the occasional visits by foreign yachtsmen and fishermen cannot be monitored from Kiritimati. A fire in 1977 possibly caused by visitors threatened breeding seabirds, and this remains a potential threat, particularly during periods of drought.