How St. Clair Got Its Name
In 1852, Harriet Beecher Stowe's novel gained popularity throughout the continent. Uncle Tom's Cabin fuelled public debate about slavery as the American Civil War approached. It is said to have made a great impression mostly on women and young boys.
'[T]he American planter is "only doing, in another form, what the English aristocracy and capitalists are doing by the lower classes"; that is, I take it, appropriating them, body and bone, soul and spirit, to their use and convenience.'
These words spoken by the benevolent slaveholder, Augustine St. Clare who frees Uncle Tom, may have impressed upon young Albert Grainger, who lived on a farm at St. Clair and Avenue Road. He adopted "St. Clair" as his middle name and used it as an alias when his military band with the Queen's Own Rifles, played at the Opera House. As a joke, he nailed a sign with the misspelt name to a tree - which surveyors took as a street sign for the Third Concession from the Bay.
You can find the correct spelling at Dufferin - St. Clare Catholic School and St. Clare Church.
Plaque via Alan L. Brown's site Toronto Plaques. Full page here.