New Guinea is not only by far the largest island in Melanesia; it is also the second largest island in the world, with an area estimated at about 312,000 square miles. It is approximately 1300 miles long-nearly half as great an east-west spread as the United States and nearly one-third that of all Melanesia--and in its widest central portion it is nearly 500 miles wide. In outline it resembles a giant bird, with its open beak and long, slender neck outstretched toward Borneo and its graceful, tapering tail curving southeastward toward New Zealand.
There are several deep indentations of the shoreline, notably MacCleur Gulf and Geelvink Bay in the west--both rather broad, shallow embayments fringed with mud flats and swampy shores--and Huon Gulf, Collingwood Bay, Milne Bay, and the Gulf of Papua in the east, all of which are deeper and have more approachable shores. Offshore coral reefs and sandy beaches line the coast in places, the coral providing numerous hazards to navigation as well as extensive, protected anchorages inside the reefs, where deep-water channels transect the obstructions and give access to the sheltered waters within. The spacious roadstead off Finschhafen and Lae in northeastern New Guinea could accommodate the combined fleets of the entire world, and so, too, could the immense basin rimmed and protected by the Bismarck Archipelago and Admiralty Islands just to the north. Both functioned as Allied naval bases for a time in 1944 during the Second World War, just as earlier Port Moresby and Milne Bay accommodated great Allied fleets, and later Hollandia, in Dutch New Guinea.