It is formed by the confluence of the north and south branches at 42°15′17″N 85°55′36″W / 42.25472°N 85.92667°W / 42.25472; -85.92667[1][2][3] in Waverly Township in the northeast of Van Buren County.

The Sarett Nature Center owns 800 acres (3.2 km2) of along the river in Berrien County, just north of Benton Harbor.

The mainstem is a coolwater stream as evidenced by the presence of burbot and mottled sculpin, it also contains hornyhead chub, common shiner, johnny darter, and walleye.

The fish community near the mouth is influenced by its proximity to Lake Michigan, and steelhead trout (Oncorhynchus mykiss) are stocked there.

Potamodromous trout and salmon have access to most of the river system, and are shore-fished in the fall upstream of Hartford.