The Labau Association occurs sporadically in the valleys of the upper reaches of many rivers. It was first described in the valley of the Sungai Labau in the headwaters of the Kinabatangan. Other notable occurrences are:
In the Kuamut Valley,
In the Sook, Keningau, Tenom, Tambunan, Ranau and Lohan Plains,
In the Labuk valley between Rumidi and Budu, and above Tampias,
In the Umas Umas Valley, and
the Brantian Valley.
The association occurs on narrow valley floors with eyots, levees, narrow floodplains and terraces. The soils are formed on alluvium, which is derived mainly from sedimentary rocks, often coarse-textured.
In the Tongod, Mankawagu, Labau and Pinangah below Inarat, the land is under shifting cultivation. Above Inarat and in the Kuamut, however, there is little habitation but some areas were once under shifting cultivation.