Its upper course is through a narrow valley bordered by steep, rocky hills. Upon the line of Wyoming and Livingston counties, it breaks through a mountain barrier in a deep gorge and forms the Portage Falls. Below this point the course of the river is through a valley  wide and bordered by banks  high.
The river's upper section winds its way through a narrow, secluded pass between steep hills. As it approaches the border of Wyoming and Livingston counties, it bursts through a mountain wall in a deep, narrow canyon and forms the Portage Falls. From this point on, the river flows through a wide, open valley with towering banks.