The Thames flows southwest for 273 kilometres (170 mi)[3] through southwestern Ontario, from the Town of Tavistock through the cities of Woodstock, London and Chatham to Lighthouse Cove on Lake St. Clair.

Downriver from London, the lower part of the Thames flows through a shallow plain of sand and clay, with an average depth of 1.2 metres (4 ft).

Urban areas the lower Thames flows through include Delaware, Chatham, Thamesville, as well as Chippewa and Oneida First Nations settlements.

In the final decades of the 19th century, pleasure boats began to operate on the Thames in London, offering service between the city and Springbank Park in Byron.

In the early morning hours of July 11, 1883, heavy rainfall caused considerable flooding on the Thames, especially in London.

The vessel Princess Louise, which had been laid up, was forced over Waterworks Dam and capsized, killing 7, while the Forest City was cast out into the river and partially damaged.

On April 27, 1937, the Thames River reached an all-time high of 21.5 feet (6.6 m) above normal flow resulting in 5 deaths and over 1000 homes being damaged.

A fourth dam at Springbank Park, downstream from the Forks, controlled water levels in central London from the 1870s until 2005 when it was closed for rehabilitation.