Identification. The Iatmul live along the banks of the Middle Sepik River in the East Sepik Province of Papua New Guinea.
Location. The Middle Sepik area is dominated by the meandering river that regularly floods the whole valley and continuously changes its course as it flows from west to east into the Bismarck Sea. During the wet season, extremely heavy rains raise the water level 4-6 meters, turning the whole region into a lake that extends far into the northern grasslands (turning them into swamp) and to the Sepik Hills in the south. Floating grass islands, sometimes with whole trees and birds on them, are typical for that season as the rising floodwaters tear off parts of riverbanks and carry them downstream until they get stuck somewhere else. Iatmul territory begins about 230 kilometers up from the mouth of the Sepik and ends about 170 kilometers farther upstream. The Iatmul lead an almost amphibian way of life within the two main seasons, wet and dry, each lasting for five months with two intermediate months in between.
Demography. The Iatmul number about 10,000, and classify themselves into three territorial subgroups: eastern (Woliagui), central (Palimbei), and western (Nyaura). During the last few years many Iatmul have left the Middle Sepik, with nearly 50 percent of the population today living elsewhere in Papua New Guinea, temporarily or even permanently. There are Iatmul colonies, sometimes of considerable size, in the towns of Wewak, Madang, and Rabaul (on New Britain).
Linguistic Affiliation. Iatmul is joined with Abelam, Boiken, Sawos, and other Papuan languages in the Ndu Family of the Sepik-Ramu Phylum.