The Scarborough Bluffs are a line of clay and sand cliffs about 15 kilometers (9 miles) long on the Lake Ontario shore in eastern Toronto. Sources give their greatest height as anything from about 65 meters to 100 meters. Elizabeth Simcoe, who saw them in 1793, is credited with the name, taken from Scarborough, England, and the township later took it. The cliffs are layered glacial and lake sediments, and they are still eroding.
Size and extent
The Canadian Encyclopedia says the bluffs run about 15 kilometers along the lake and rise up to 100 meters above the shore. A Heritage Toronto account reproduced by UrbanToronto gives about 14 kilometers and roughly 65 meters (“some 65m above the water”). No official survey figure was reached for this article, so the height is shown as a range. The article on Toronto’s elevation and topography gives the broader picture of how the ground rises from the lake and explains the old shoreline of Glacial Lake Iroquois.
How the name came about
The Canadian Encyclopedia says Elizabeth Simcoe, wife of Lieutenant Governor John Graves Simcoe, gave the bluffs their name. She first saw them in 1793, and the Encyclopedia quotes her diary: the shore “is extremely bold & has the appearance of Chalk Cliffs.” The Toronto Public Library’s local history blog places the entry on August 4, 1793, adds that the cliffs were probably white sand rather than chalk, and says the Simcoes only mused about a summer residence there and about naming the area after Scarborough in North Yorkshire, England. Her life is covered in the biography of Elizabeth Simcoe.
The record on the township’s name is thin. The Heritage Toronto account says John Graves Simcoe renamed the new township north of the highlands Scarborough from Glasgow, but none of the sources read for this article gives the year of that change. The township’s own history is in the article on Scarborough.
What the cliffs are made of
The Canadian Encyclopedia calls the bluffs the remains of an ancient, now eroded lake delta, with a geological record of early life preserved in fossil plants and animals. The Heritage Toronto account says the sediments in the first 46 meters hold fossils left as the Wisconsinan glacier advanced about 70,000 years ago, and that above them lie boulder clay and sand from four advances and retreats of ice. The last glacial retreat in the area, it says, was about 12,000 years ago.
The ages of the named layers are given as ranges. The volunteer-run Lost Rivers project gives the Scarborough Formation as 115,000 to 106,000 years old, the Pottery Road Formation as 106,000 to 75,000 years old, and the Sunnybrook Drift as 60,000 to 75,000 years old, laid down in a high-level lake similar to Lake Iroquois. It says the delta was large enough to protect the Don Beds from complete destruction by the advancing Wisconsinan ice sheet, preserving evidence of a warm interglacial stage. A university source, the Planet Earth Lab at the University of Toronto Scarborough, describes the cliffs below Scarborough Crescent Park as mainly glaciolacustrine sediments laid down in large glacial lakes as the Laurentide Ice Sheet advanced, resting on older sands and clays and capped with sand from the shores of Lake Iroquois. The two sources use different layer names, so no single age is given here. Readers who need a date should consult the Geological Survey or university sources directly.
The same layers are exposed in the quarry of the Don Valley Brick Works, described in its own article. The Planet Earth Lab adds that sediment from the eroding cliffs was moved west by longshore transport and built spits that became the Toronto Islands; the history of the harbor and islands is in the article on the Toronto waterfront.
Erosion and shoreline works
Erosion is the main fact of the bluffs. The Planet Earth Lab says waves pound the base of the cliffs until the face fails, that the shoreline is a transgressive coast where rising lake levels drive recession, and that saturation of the sand at the top can reduce stability. The Canadian Encyclopedia notes that erosion still occasionally threatens houses at the cliff’s edge. CTV News reported on August 24, 2020 that part of the bluffs had collapsed onto a beach; the page read for this article gave no further detail, so no injuries, cause or exact location are stated.
Two public projects now deal with the shoreline. The Scarborough Waterfront Project, led by the Toronto and Region Conservation Authority (TRCA), covers the shore from Bluffer’s Park to East Point Park and Highland Creek, according to Ontario’s project page; the Minister of the Environment, Conservation and Parks approved its environmental assessment on September 13, 2019. The Scarborough Bluffs West project, led by the City of Toronto and the TRCA, covers the area from the Eastern Beaches to Bluffer’s Park. The City says Council named it a priority in 2021, that the terms of reference were approved on October 1, 2025, and that most of the shoreline is already modified by seawalls, armourstone revetments, and a beach and groyne system maintained by the TRCA. The City says no funding is secured for design or construction. Both projects change, so the City and TRCA pages are the source for their present status.
Parks on the bluffs
The Canadian Encyclopedia describes Bluffer’s Park, at the water’s edge, as a recreation area built from lakefill. Public ownership and park boundaries along the bluffs are set by the City of Toronto and the TRCA, whose pages should be checked for the current parks and trails. The article on Scarborough covers the township and borough that once held this shoreline.
Frequently asked questions
How high are the Scarborough Bluffs?
Sources disagree: about 65 meters (Heritage Toronto) and up to 100 meters (Canadian Encyclopedia). Neither is an official survey.
Who named the Scarborough Bluffs?
The Canadian Encyclopedia credits Elizabeth Simcoe, who saw them in 1793 and wrote that they looked like chalk cliffs. The Toronto Public Library says she and her husband considered naming the area after Scarborough in North Yorkshire, England.
How old are the cliffs?
The Lost Rivers project places the named layers between roughly 115,000 and 60,000 years ago, and the Heritage Toronto account puts the last ice retreat at about 12,000 years ago. The sources use different layer names, so the ages are not given as one settled figure.
Can the bluffs be climbed or walked at the base?
Public access and safety rules change with erosion. The City and the TRCA publish current warnings, and the City notes that people currently reach the shore by informal paths that, in its words, impact the natural environment.
Last verified: October 2026
Sources
- The Canadian Encyclopedia, “Toronto Feature: Scarborough Bluffs,” Historica Canada
- Government of Ontario, “Scarborough Waterfront Project”
- City of Toronto, “Scarborough Bluffs West” project page
- Heritage Toronto account, “Heritage Toronto Mondays: Scarborough Bluffs,” UrbanToronto, April 18, 2011
- Lost Rivers project, Scarborough delta and formations page
- Toronto Public Library, Local History and Genealogy blog, “Elizabeth Simcoe’s Diary Finds “Scarborough” on August 4: Snapshots in History,” August 2016
- Andrew Zajch, “Beautiful but dangerous: Scenic spots and hazards at the Scarborough Bluffs,” Planet Earth Lab, University of Toronto Scarborough, January 2021
- Chris Herhalt, “Beachgoers shocked as part of Scarborough Bluffs collapses,” CTV News Toronto, August 24, 2020
Related reading
- Scarborough, the township and borough behind the bluffs
- Elizabeth Simcoe, who named the highlands
- Toronto’s elevation and the old lake shore
- The Brick Works quarry and its exposed layers
- Toronto Harbour and the waterfront
- Toronto facts: location, geography, and weather
Cite this page
APA: History of Toronto. (2026, October 23). The Scarborough Bluffs: History, Name, and Geology. https://historyoftoronto.ca/blog/scarborough-bluffs-history
MLA: “The Scarborough Bluffs: History, Name, and Geology.” History of Toronto, 23 Oct. 2026, https://historyoftoronto.ca/blog/scarborough-bluffs-history. Accessed .
Chicago: History of Toronto. “The Scarborough Bluffs: History, Name, and Geology.” Last modified October 23, 2026. https://historyoftoronto.ca/blog/scarborough-bluffs-history.
The pages have no named author, so the site is given as the author. Add the date you read the page if your style asks for it.