The Architectural Conservancy of Ontario (ACO) was founded in 1933. The organization was initiated by the saving of Barnum House near Grafton, which is now owned and operated by the Ontario Heritage Trust. Today, the ACO operates as a decentralized organization with 25 branches across Ontario and a central provincial headquarters located in Toronto. The ACO has helped to save hundreds of heritage buildings across Ontario, and has raised awareness of the importance of preserving Ontario’s provincial, municipal, and community heritage. As the first organization to do such work, ACO pressed for heritage legislation and funding in Ontario, and has been followed in the field by such outstanding organizations as the Ontario Heritage Trust, Community Heritage Ontario, and the Canadian Association of Heritage Professionals.
The ACO Port Hope Branch was founded in 1964. Since then, it has become one of the most active and financially successful of the ACO branches with almost 500 members.