The source of the river is located in the area of
Warren's Gore, Vermont, on the northwest flank of
Bluff Mountain in
Essex County, Vermont. This source is located at: • West of a summit of the
Bluff Mountain; • Southwest of the summit of the
Middle Mountain; • Northeast of the border of
Orleans County; • North of
Island Pond. From its source, the river Pherrins flows on according to the following segments: • toward the Northwest racing down the cliff on down to the railway crossing the valley of Pherrins River and the
Coaticook River; • toward the Southwest, crossing two small lakes up to the confluence of a stream (from the North); • toward Southwest, up to the limit of
Orleans County; • toward the Southwest, collecting the waters of a mountain stream (from the Northwest) up to the Pine Brook (from the East); • to the South up to the discharge of Underpass Pond (from the East); • to the South up to the limit of
Essex County; • to the Southeast up to its confluence The Pherrins River empties on the Northwest shore of the
Clyde River at downstream from the mouth of the
Island Pond in the area of
Brighton, Vermont. This confluence is located on the west side of
Island Pond. ==Toponymy==