"Summit House"
This house was built in 1823 by James Boulton, one of Perth's first lawyers. Modelled after "The Grange" in Toronto, the house was designed in the Adamesque style, which was popular in Upper Canada during the 1820s, with overtones of the Regency style, which superceded the Adamesque in the following decade. The graceful fanlight over the main entrance and the oval window in the central gable are typical of the earlier style, whereas the tall first-floor windows and the hip roof reflect the influence of the Regency. The use of brick on a large dwelling at so early a date is rare in this province, and the "Summit House" is one of the first examples, constructed of this material, in the Adamesque or Regency style.
Plaque via Alan L. Brown's site Ontario Plaques. Full page here.