Near Glenfield the Black River receives the smaller tributaries of Otter Creek and the Independence River, also from the east. Further north, it passes Lowville, then receives the Beaver River from the east, then the Deer River, its only major western tributary. Starting above Carthage the river briefly divides Lewis and Jefferson Counties before crossing entirely into Jefferson County, where it turns sharply west toward Lake Ontario, flowing past Great Bend, Black River and Watertown. Below Watertown it enters a canyon, well known for its challenging rapids.