Black Brook is a town in Clinton County, New York, United States.

Black Brook occupies the southwestern corner of Clinton County and is southwest of Plattsburgh.

Black Brook, a tributary of the West Fork of the Au Sable River, flows southward through the center of the town.

The outlet of Union Falls Pond, a reservoir on the Saranac River, is in the western section of the town.

New York State Route 9N passes across the southeastern part of the town, leading east to Keeseville and southwest to Jay.

New York State Route 3 crosses the northwestern corner of the town, leading northeast to Plattsburgh and southwest to Saranac Lake.