Peterborough

City in Ontario, Canada, on the Otonabee River, 113 km/70 mi northeast of Toronto and 45 km/28 mi north of Lake Ontario; population (1991) 68,400. Peterborough is the chief commercial centre for central Ontario. It has a large cereal mill and electrical-goods plant and also manufactures marine equipment. The world's largest deposit of nepheline, used in the manufacture of glass, is mined north of the city, and the refined product is shipped to the glass industry round the world. The surrounding lake district area attracts tourists.

Peterborough is on the Trent Canal, an inland waterway, joining Lake Ontario with Georgian Bay. A hydraulic lock built 1904 is one of only eight of its kind in the world, producing a difference in water level of 20 m/66 ft.

Peterborough is the seat of Trent University.