The Rassokha is formed by the confluence of the rivers Ilin-Yuryakh and Arga-Yuryakh in the Kolyma Lowland. The original sources of the uppermost river in the network are in the Ulakhan-Sis Range. The Rassokha flows across the Middle Kolyma District and the Lower Kolyma District in an area marked by permafrost, with numerous swamps and lakes. Finally it joins the left bank of the Alazeya from its mouth.