The Ontario Heritage Act (OHA) empowers municipalities and the province to designate property of cultural heritage value or interest. Recognizing the importance of heritage sites to the collective memory of all Ontarians, the OHA requires that the province keep an official record of all properties and heritage conservation districts designated under the act, and of any other properties that the Minister of Tourism, Culture and Sport considers to be of cultural heritage value or interest.

The OHA Register is a central repository of legal documents, including designation bylaws, statements of cultural heritage value or interest, descriptions of heritage attributes, notices of council decisions, approvals for alterations and ministerial orders. It provides information for municipalities, planners, property owners, lawyers, heritage organizations, researchers and the general public.

This important resource documents municipally designated heritage properties across Ontario. In a rapidly changing environment, it is a valuable tool to build understanding of the heritage of our communities – an important step in protecting, preserving and promoting these sites for the future.

Since the mid-20th century, many communities around the province have experienced tremendous growth. The resulting development has destroyed much of our built heritage. But some communities have faced slower economic expansion that has preserved their streetscapes and landscapes, while still others have planned well to conserve the
natural and cultural heritage features that make them unique. The OHA Register is a valuable resource that documents these heritage conservation efforts.

The Register is a useful tool in understanding how designated properties have value beyond their community – they are part of the cultural fabric of Ontario. They are as unique and diverse as the Kenricia Hotel in Kenora, Precious Blood Cathedral in Sault Ste. Marie, Layer Cake Hall in Bath, Peterborough’s Market Hall and Clock Tower, Gooderham & Worts Distillery in Toronto, Whitehern Historic House and Garden in Hamilton, the William Stewart Homestead in Niagara-on-the-Lake, St. John's Anglican Church Cemetery in Windsor and Bellevue House in Amherstburg, as well as heritage conservation districts in communities that include Seaforth, Cobourg, Kingston, Mississauga and Ottawa.

Until March 31, 2010, the OHA Register had been administered by the then-Ministry of Tourism and Culture. It is now managed and maintained by the Ontario Heritage Trust. Maintaining the Register is one of the ways that the Trust is working to support heritage conservation across the province.