The Tay River is a river in Lanark County in Eastern Ontario, Canada. It is in the Saint Lawrence River drainage basin and is a left tributary of the Rideau River. The Tay River watershed, covering a drainage area in excess of 800 square kilometers, is the westmost of the 6 recognized subwatersheds managed by the Rideau Valley Conservation Authority. Course This river starts at Bobs Lake and leaves the lake, controlled by a weir, near the community of Bolingbroke in geographic South Sherbrooke Township, part of the municipality of Tay Valley. It heads northeast, passes under Lanark County Road 36, reaches Christie Lake and passes there into geographic Bathurst Township. It continues northeast, passes under Lanark County Road 6, and divides into two channels; the right channel is known as Scotts Snye. The river then travels through the community of Glen Tay, continuing to Perth. The river splits into two main channels as it flows through downtown Perth. The two channels have recombined by the time it leaves Perth and continues to the Rideau River, which drains via the Ottawa River into the Saint Lawrence River. The river is in length and drains an area of . A canal connects the river to the Tay Canal, and Rideau Canal systems at Beveridge Bay on Lower Rideau Lake. Lakes in the Tay watershed Top of Watershed (above north-south railroad line from Oconto to Tichborne) Abbott, Barton, Carnahan, Clow, Danby, Duncan, Eagle, Elbow, Leggat, Little Beaver, Little Mud, Long, Miller, Oconto, Scanlin, Spruce, Watson Middle watershed (between Oconto/Tichborne line and Christie Lake) Atwood, Beaver, Bobs & Crow, Buck Bay, Burns Pond, Christie, Crosby, Davern, Deer, Doran, Farrell, Green Bay, Lake of the Hills, Little Crosby, Little Rock, Little Silver, Little Twins, Lynn, Mud Bay, O’Brien, Pike, Rainbow, Rock (north), Sucker, Thompson Pond, Victoria, Weatherhead Below Christie Lake Andrew, Doctor McLaren, Mills, Mud, Otty, Rock (south), Thoms Mud History The Tay River was formed during the retreat of the Champlain Sea after the last ice age. The name given to it by the Mississauga First Nation, who controlled its territory at the time of the arrival of the first European settlers, appears to have not been recorded. They used its territory for hunting, especially in the winter, and likely harvested manoomin (wild rice) on some of its lakes, for instance Christie Lake. Early European settlers called it the Pike River; the name