For heritage groups

Ask your municipality to open its heritage register

Every Ontario municipality must publish its heritage register, but only some publish it as open data that tools like this one can use. When yours does, its buildings appear here with alerts, priority scores and everything else, for free. A short letter from residents is often what makes it happen.

Not on The Patina Record yet

Ottawa: No open data. A register extract has been requested from the City.
Markham: Its map reads a protected layer; the site's terms allow viewing only. Permission requested.
Vaughan: Public map layer with no open licence. Permission requested.
Richmond Hill: Public map layer with no open licence. Permission requested.
Waterloo: Public layer (2018) with no open licence. Permission requested.
Peterborough: Public layer with no open licence. Permission requested.
Collingwood: Public layer with no open licence. Permission requested.
Cornwall: Public layer with no open licence. Permission requested.
Lincoln: Public layer with no open licence. Permission requested.
Greater Sudbury: The City is moving its register to its open data portal.
Centre Wellington: A register extract has been requested from the Township.
Caledon: Its map reads a protected layer.
Thunder Bay: Open data CSV (2022) without locations; not yet mapped.
Anywhere else not listed below: not checked yet. Ask, and tell us.

Write to your municipality

MunicipalityYour nameGroup (optional)

Your letter (send it to the clerk and heritage planning)

Subject: Request: publish the [municipality] heritage register as open data

Dear Clerk and Heritage Planning staff,

I am writing to ask [municipality] to publish its municipal heritage register as open data, under an open licence such as the Open Government Licence.

The Ontario Heritage Act already requires the register to be public. Publishing it as a dataset (CSV, GeoJSON or an open map layer) lets residents, heritage groups and free tools such as The Patina Record (https://thepatinarecord.ca) follow listed and designated properties, especially ahead of January 1, 2027, when listed properties without a notice of intention to designate come off municipal registers.

The most useful fields are: address, status (listed or designated), Part IV or Part V, by-law number and date, the date a property was listed, and a location. Updating it when council makes a change would keep it reliable.

Thank you for considering this.

[Your name]

The tracker shows the municipality, the date and your group name if you give one; never your name or email.

Who has asked

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Already open (41)

Ajax · Aurora · Brampton · Burlington · Cambridge · Chatham-Kent · Clarington · Cobourg · Collingwood · Fort Erie · Georgina · Greater Sudbury · Grimsby · Guelph · Hamilton · Kingston · Kitchener · Lincoln · London · Milton · Mississauga · Niagara Falls · Niagara-on-the-Lake · Oakville · Orangeville · Oshawa · Pelham · Pickering · Port Colborne · Port Hope · Prince Edward County · St. Catharines · St. Marys · Thorold · Thunder Bay · Toronto · Wainfleet · Welland · West Lincoln · Whitby · Windsor

Licences for each are on the sources page. Some come from a register PDF or an extract the municipality sent, not a live open dataset.