The river flows in a generally northwest direction, with its valley dividing the Adirondack Mountains on the east from the Tug Hill region to the west.

The Black River originates at North Lake in the foothills of the Adirondacks, in Herkimer County, about 25 miles (40 km) east of Boonville.

In contrast the middle 40 miles (64 km) of the river have practically no gradient and are not suitable to the development of head for industrial or hydropower projects.

The other dams are run-of-the-river, with no appreciable storage capacity, so power generation is entirely dependent on the natural flow of the river combined with releases from upstream reservoirs, which is relatively consistent except for drought years.

[10][11] As of August 3, 2006, a settlement has been reached and Marks Dairy Farm, originator of the spill, was ordered to pay $2.2 million.