The Bonnechere River watershed encompasses an area of 2400 sq km (935 sq mi), and over 80% of this land is privately owned.
The Bonnechere River is over 145 km (90 mi) long and begins in Algonquin Park on the Canadian Shield and flows into the Ottawa River at Castleford, Ontario. Along its length, the river’s character changes from cold and clear to warm and turbid as it flows from its forested, rocky source to open farm land with more erodable clay soils, human settlement and scattered woodlots. Golden and Round lakes, two of the largest lakes in Renfrew County are situated on the Bonnechere.
The area of land encompassed by a watershed could be very small or it could be immense. For example, Smith’s Creek in Renfrew is a sub-watershed of the Bonnechere River watershed. The Bonnechere River watershed is a sub-watershed of the Ottawa River, which is part of the St. Lawrence River watershed, which in turn is one of the watersheds that flows into the Atlantic Ocean.