Leslie Street Spit and Tommy Thompson Park History

The Leslie Street Spit is a man-made peninsula about five kilometres long that reaches into Lake Ontario from the foot of Leslie Street. The Toronto Harbour Commissioners began building it in 1959 from dredged sand and silt and from demolition rubble. It was meant to shelter a larger port that never came. It is now Tommy Thompson Park, a nature reserve run by the Toronto and Region Conservation Authority, known for migrating birds and one of the largest cormorant colonies on the Great Lakes.

A breakwater for a port that never grew

The Spit started as an engineering project. In 1959 the Toronto Harbour Commissioners began creating new land at the foot of Leslie Street. The commission intended it as a barrier to protect a planned outer harbour from waves on Lake Ontario, and as space for port-related facilities. The year matters, because the St. Lawrence Seaway opened in 1959 and Toronto expected a surge in shipping.

The expected boom did not arrive. The commissioners’ wider story, including the filling of the marsh to the west, is told in Toronto Harbour Commission and the Port Lands. By the early 1970s the province accepted that the breakwater was no longer needed for a new port.

What the land is made of

Everything on the Spit was put there by people. The earliest fill was brick and concrete rubble from demolition sites. Heritage Toronto notes that mud and sand dredged from the lake bottom went in alongside bricks and cement from downtown homes and shops. Much of the brick rubble dates to the 1960s, and some came from 19th-century row houses in the Alexandra Park area. Sections built in 1964 contain household items such as teacups, medicine bottles and eyeglasses. Rubble in other parts is linked to the skyscraper boom of the 1980s, when many old brick buildings came down.

The Canadian Encyclopedia adds debris from building high-rises and subways. The Narwhal says hundreds of trucks a day brought material in the busiest years. Subway construction of the period, such as the line in the Bloor-Danforth subway article, was one source of spoil. The Toronto and Region Conservation Authority’s park site reports roughly 6.5 million cubic metres of sand and silt dredged from the outer harbour between 1974 and 1983, and an expansion in 1979 that took dredged material from the inner harbour and the Keating Channel.

From dump to conservation area

In the early 1970s the project changed course. The Toronto and Region Conservation Authority describes the province making it its agent for a proposed park in 1973, with its role widened in 1977 to include public access. The Canadian Encyclopedia, by contrast, says the authority had taken over much of the Spit and opened it on weekends by 1973. Heritage Toronto gives the 1970s generally. Treat the exact year of first public opening as uncertain.

Plans in the late 1970s proposed an amusement area, a hotel and a marina on the Spit. Local activists helped keep it natural. The peninsula is now named for Tommy Thompson, Metropolitan Toronto’s first parks commissioner, who influenced the design of Toronto Island Park and worked to keep the city’s ravines wild. His title came from the regional government described in the article on Metropolitan Toronto. The sources used here do not agree on the year of the naming, so none is given.

Size and layout

The Spit extends about five kilometres into Lake Ontario and covers roughly 500 hectares. It is a long finger of land with marshes, ponds and a cottonwood forest that grew up on the fill. The park attracts more than 100,000 visitors a year, according to its own materials.

Part of the Spit remains working land. Dredged sediment from harbour maintenance is placed in landlocked areas called cells, rather than in the open lake as in the past. The conservation authority has turned two cells into wetlands, and PortsToronto still uses a third. Because of truck traffic, public access has been limited to weekends, holidays and certain weekday hours. Check the conservation authority before visiting, since hours and closures change.

Birds and the cormorant colony

Birds colonized the Spit before anyone planned for them. Seasonal wet areas draw migrating shorebirds and nesting rails, and the forest supports colonial tree-nesting birds and songbirds. By 2013 the park was designated both an Environmentally Significant Area and an Important Bird Area. A bird research station on the site supplies banding data to the Canadian Migration Monitoring Network, which has 26 stations.

The best-known residents are double-crested cormorants. The species almost vanished from the Great Lakes in the 1960s because DDT thinned the shells of their eggs. After DDT was restricted, the population recovered. The Narwhal reports that six pairs nested at the park in 1990, and that by 2021 there were more than 10,000 nests, which it describes as the largest breeding colony of the species in North America.

The colony has a cost. Droppings damage trees. Rather than a cull, park staff discourage nesting in healthy trees and encourage ground nesting. Some peninsulas are closed to visitors from April 1 to September 1 so the birds can breed.

How to place the Spit in Toronto’s story

The Spit sits beside the oldest plans for the harbour. The bay it shelters is the one that gave Toronto its early economy, covered in the harbour and waterfront article. East along the same lake shore, the Scarborough Bluffs are a natural landform, which makes a useful contrast with this built one.

The Spit is a case of an engineering project that missed its original purpose and became habitat. The land exists because Toronto expected a larger port than it got, and because contractors needed a place to put rubble.

Visitors today walk or cycle the long central road, and the conservation authority publishes bird checklists and breeding-bird reports each year. The Spit and the Port Lands were both shaped by the same harbour agency, and their stories are best read together.

Frequently asked questions

When was the Leslie Street Spit built?

Construction began in 1959, when the Toronto Harbour Commissioners started placing fill to create a breakwater and land for port facilities. Filling has continued in stages since then.

Why is it called Tommy Thompson Park?

The park is named for Tommy Thompson, Metropolitan Toronto’s first parks commissioner. The Spit is named after Leslie Street, the road that ends where it begins.

What is the Spit made of?

Dredged sand and silt, plus brick, concrete and other debris from demolished buildings and construction sites across Toronto.

How many cormorants nest at Tommy Thompson Park?

Six pairs nested in 1990. By 2021 there were more than 10,000 nests, according to The Narwhal. Annual counts are published by the conservation authority.

Can anyone visit the park?

Public access has been limited to weekends, holidays and some weekday hours because of ongoing port work. Check the Toronto and Region Conservation Authority for current hours and closures.

Sources

Heritage Toronto, “Tommy Thompson Park history” (accessed October 2026)
Toronto and Region Conservation Authority, Tommy Thompson Park, “About” (accessed October 2026)
The Canadian Encyclopedia, “Toronto Feature: Tommy Thompson Park” (published 2013, last edited 2015)
The Narwhal, article on birds at Tommy Thompson Park (accessed October 2026)
Toronto Port Authority, “History” (Toronto Harbour Commissioners timeline, accessed October 2026)
Port Lands Toronto, “History of the Port Lands” (accessed October 2026)

Last verified: November 2026

Cite this page

APA: History of Toronto. (2026, November 1). Leslie Street Spit and Tommy Thompson Park: How a Dump Became a Park. https://historyoftoronto.ca/blog/leslie-street-spit-history

MLA: “Leslie Street Spit and Tommy Thompson Park: How a Dump Became a Park.” History of Toronto, 1 Nov 2026, https://historyoftoronto.ca/blog/leslie-street-spit-history. Accessed .

Chicago: History of Toronto. “Leslie Street Spit and Tommy Thompson Park: How a Dump Became a Park.” Last modified November 1, 2026. https://historyoftoronto.ca/blog/leslie-street-spit-history.

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