Modern Mississauga presents Way Back Wednesdays - The history of Ninth Line and Tenth Line West

Modern Mississauga and Heritage Mississauga have come together to present an ongoing series called “Way Back Wednesdays."
We’ll share information about the history of Mississauga here and answer your questions.
Today’s topic is the history of Ninth Line and Tenth Line West.

Barn raising, McCarron farm, c1900.jpg

With Mississauga’s recent extension of our western border to west of Ninth Line, large
portions of land which were once part of Trafalgar Township and Halton County are now
part of the City of Mississauga and the Region of Peel. The historical difference is
evident on the landscape in the form of two specific road names: Ninth Line and Tenth
Line West. Lines, which are basically North-South running roads, were first surveyed
between 1806 and 1819 through Peel and Halton Counties. Each county had a “base
line” or starting point. In historic Mississauga, the Lines ran parallel to Centre Road (now
Hurontario Street), spaced at even intervals and numbered sequentially. For instance,
Mississauga once had a Second Line East, which identified the second North-South
road east of and running parallel to Centre Road (Second Line East is now known as
Tomken Road).

Most of the numbered lines received names over the years, with only segments of
Second Line West and Fifth Line West retaining their original numerical designations.
For instance, Sixth Line West (also known as the Town Line) was renamed to Winston
Churchill Boulevard in the 1960s, while First Line East and Third Line East now carry the names of Cawthra Road and Dixie Road respectively.

Tenth Line West road sign.jpg

However, the numbering system for Halton County was slightly different. There was no “centre point”, therefore no “east” or “west” designation was required. The starting point for survey of Halton was what is known today as Tremaine Road, and the Lines (North-South Roads running parallel to Tremaine Road at regular intervals) were surveyed eastward, ending when they
“bumped into” the Peel County border. In this manner, ten “Lines” were surveyed.

Ninth Line and Tenth Line, portions of which are now within Mississauga, originally belong to
the Trafalgar survey. In this manner, the Sixth Line or Town Line of Toronto Township
(now Winston Churchill) runs adjacent and parallel to Tenth Line of Trafalgar Township.
It is a significant, if subtle, reminder of the historic roots of our community. Perhaps
unknowingly, Mississauga designated part of Tenth Line as “Tenth Line West”, when in
historic survey terms it is not actually “west” of anything; rather it marks the last surveyed
line of a survey which radiated eastward from Tremaine Road.

If you’ve got a question about the history of our city, we want to hear from you.
Please send your questions to with “Way Back Wednesday” in the subject line.