The Toronto Harbour Commissioners were created by federal law in 1911 to run the harbour and waterfront. Their 1912 plan filled the Ashbridges Bay Marsh, built the Ship Channel and produced the industrial land now called the Port Lands, about 400 hectares in all. Since 2017 the Port Lands Flood Protection project has been cutting a new mouth for the Don River through the same ground. For the wider story of the shoreline, see Toronto harbour and waterfront history.
A marsh at the mouth of the Don
Before there were Port Lands there was a marsh. The Ashbridges Bay Marsh, at the east end of Toronto Bay, was among the largest freshwater marshes on Lake Ontario. Elizabeth Simcoe described the area in 1794 as low land covered with rushes. Her diaries and the settlement of the town are covered in our article on her.
The marsh did not last as the town grew. Sewage from Toronto reached the lower Don River in the late 1800s, and mill dams blocked fish. Breakwaters built in the 1870s began to change the shoreline. Port Lands project materials say the ecosystem of the marsh had deteriorated completely by the end of the century. The creeks and ravines that fed Toronto’s bay are explained in Lost Rivers and Ravines.
The Keating Channel and the first changes
In the 1890s the city moved the mouth of the Don. The Keating Channel was built along the northern edge of the marsh, named for the city engineer Edward Keating, and the river was directed into its lined channel. Sources differ on exact dates. Some credit Keating with proposing the channel in 1893. The Port Lands project history places construction in the late 1890s. The result was a river that turned sharply near its mouth, which increased the risk of flooding in the low ground nearby.
The channel was the first step. The larger change came after the federal government created a new body for the waterfront.
The Toronto Harbour Commissioners, 1911
Toronto had a harbour trust as early as 1850, when five commissioners were appointed to manage the harbour. The modern body came in 1911, when Parliament passed the Toronto Harbour Commissioners Act. According to the Toronto Port Authority’s history, the commission was a joint federal and municipal agency responsible for the harbour and the waterfront.
It presented an overall waterfront plan in 1912. Old piers were cleared, waterlots were filled and the present shape of the harbour took form. The commissioners also built quays, enlarged the Toronto Islands, which is described in our Toronto Islands article, and completed Sunnyside Park and its amusement park in 1922.
Filling the marsh: the Port Lands
The 1912 plan turned the Ashbridges Bay Marsh into an industrial district. By 1922 the marsh had been filled to give more than 200 hectares of new land, with another 200 hectares to follow. Together the Port Lands are about 400 hectares. The work included the Ship Channel and a turning basin, which allowed lake vessels to reach factories and warehouses on the filled ground.
In 1929 the commissioners completed the Ship Channel Bridge. They also built the city’s first air harbour that year, and Billy Bishop Toronto City Airport opened in 1939. A second wave of development came in the 1950s. Hearn Generating Station and the Commissioners Incinerator went up on the Port Lands, the Leslie Street Spit began in 1959 (see Leslie Street Spit history), and the Gardiner Expressway was built over the mouth of the Don, a story told in the Gardiner Expressway article.
The hoped-for boom after the St. Lawrence Seaway opened in 1959 did not come. By the 1980s the Port Lands were largely underused and served mainly for salt storage and light industry. Film studios arrived in the early 2000s.
From commission to port authority
The commissioners took over operation of the marine terminals in 1962. Between 1991 and 1994 they handed 640 acres of waterfront land to the City of Toronto and the Toronto Economic Development Corporation. In 1998 and 1999 the federal Canada Marine Act moved port administration to the new Toronto Port Authority. Official pages give both 1998 and 1999 for different steps in the change. The agency now operates as PortsToronto.
Giving the Don a new mouth
The channelled Don River kept the Port Lands exposed to flooding. A project to rebuild the river mouth was approved by an environmental assessment on January 28, 2015, according to the Ontario government. Waterfront Toronto reports that $1.25 billion in municipal, provincial and federal funding was awarded in June 2017 and construction began that December.
The work cuts a new river valley, about a kilometre long, through the Port Lands to reconnect the Don to Lake Ontario. The ground to the north becomes an island, first called Villiers Island and now named Ookwemin Minising. The project is meant to protect more than 290 hectares of land to the east and south of the river from flooding, and to open about 25 hectares of public parkland. The provincial project page also lists a smaller figure, 230 hectares, for part of the work, so treat the exact area as approximate.
Where the project stands
Milestones are documented. Water filled the new river valley in February 2024. On July 9, 2024, CP24 reported that crews had removed the West Plug, an underwater concrete wall under the Cherry Street South bridge, connecting the new river to Lake Ontario. The same report gave a cost of $1.35 billion and said flood protection was expected to be finished by the end of 2024, with parks and the new valley opening in 2025. Earlier targets slipped, and cost figures differ between sources.
This article does not confirm that every part is open or finished. Readers planning a visit should check Waterfront Toronto and the City of Toronto for current access. Development of homes and buildings is a separate step that follows the flood work.
Frequently asked questions
When was the Toronto Harbour Commission created?
The federal government passed the Toronto Harbour Commissioners Act in 1911. The commission was a joint federal and municipal agency and presented its waterfront plan in 1912.
What are the Port Lands?
They are about 400 hectares of land east of the Don River, created largely by filling the Ashbridges Bay Marsh in the early 20th century, mainly for industry.
Why is the Don River mouth being rebuilt?
The channelled river made a sharp turn near its mouth, which raised flood risk for the Port Lands and nearby neighbourhoods. The new river valley is intended to carry floodwater and protect those areas.
What is Ookwemin Minising?
It is the name now given to the island formed by the new river valley, formerly called Villiers Island.
What replaced the Harbour Commission?
The Toronto Port Authority took over in 1998 and 1999 under the federal Canada Marine Act. It now operates as PortsToronto.
Sources
- Toronto Port Authority, “History” (Toronto Harbour Commissioners timeline, accessed October 2026)
- Port Lands Toronto, “History of the Port Lands” (accessed October 2026)
- Port Lands Toronto, “About” the Port Lands Flood Protection project (accessed October 2026)
- Ontario Ministry of the Environment, “Don Mouth Naturalization and Port Lands Flood Protection Project” (page updated July 2021)
- Waterfront Toronto, “Arrival of new bridge marks milestone in Port Lands Flood Protection project” (December 8, 2021)
- CP24, “New stretch of Don River meets Lake Ontario in milestone for Toronto Port Lands redevelopment” (July 9, 2024)
Related reading
- Toronto harbour and waterfront history
- Leslie Street Spit history
- Toronto Islands history
- Gardiner Expressway history
- Leslieville history
- Lost rivers and ravines of Toronto
Last verified: November 2026
Cite this page
APA: History of Toronto. (2026, November 1). Toronto Harbour Commission and the Port Lands: Marsh to River. https://historyoftoronto.ca/blog/toronto-harbour-commission-and-port-lands-history
MLA: “Toronto Harbour Commission and the Port Lands: Marsh to River.” History of Toronto, 1 Nov 2026, https://historyoftoronto.ca/blog/toronto-harbour-commission-and-port-lands-history. Accessed .
Chicago: History of Toronto. “Toronto Harbour Commission and the Port Lands: Marsh to River.” Last modified November 1, 2026. https://historyoftoronto.ca/blog/toronto-harbour-commission-and-port-lands-history.
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