Auchmar Estate was built by Isaac Buchanan, a prominent economist and politician, between 1852 and 1854 on a private estate on 86 acres on the Hamilton Mountain that he called Clairmont Park. The 2 storey, stuccoed brick manor house is considered an elegant example of Gothic Revival style architecture with its arched windows, numerous chimneys, gables, and French doors. Auchmar is a unique, heritage asset owned by the citizens of Hamilton.

In 2009 repairs were undertaken to restore 2 deteriorated chimneys and cracked foundation walls at the northwest end of the house. Both chimneys were completely dismantled to below the roof line and rebuilt with new brick to match the original profile, incorporating new metal flashings and chimney covers. Foundations were excavated and repaired by deep repointing with lime-based mortar, parged and damp-proofed on the exterior. Interior repairs included the removal and replacement of rust-jacked wall brackets, and the repair of brick arches.