Upper Canada College Boarding House
This is the last remaining building of Upper Canada College, located here 1831-1891. Built in the Georgian style in 1833, the student residence was altered and enlarged first in 1856 by Cumberland and Storm, architects, and again several times in later years. After the school moved to its present location on Lonsdale Road, most of the buildings on this site were demolished. The residence was then used as a factory until renovated in 1985 for commercial purposes.
Plaque via Alan L. Brown's site Toronto Plaques. Full page here.