The Karamuak Association occurs:
on valley floors and terraces along the Sungai Karamuak,
in the Mananam Plain,
in the headwaters of the Bole and Segama rivers, and
along Sungai Kadamaian.
Parent materials comprise fine- to coarse-textured, sometimes stony, alluvium, derived from mixed sources, but including basic igneous rocks.
Most of the land has been cleared for shifting cultivation and is either under cultivation or more commonly at some stage of secondary regrowth.