It begins northeast of the Hamlet of Stillwater and flows into the West Branch Oswegatchie River in Harrisville.

[1] The Middle Branch mostly consists of shallow and fast-moving waters with only two or three slow-moving sections favorable for canoeists.

The latter begins in the area where Lower South Pond Outlet runs into the river.

Occasionally, experienced kayakers take advantage of high water conditions to ply its waters – generally from the Bear Pond Road, a few miles upstream of Alder Bed Flow, and downstream to another seasonal access road located near Mullins Flow.

Brook trout exist as the primary sport-fish for the entire length of Middle Branch Oswegatchie.