The life & death of Canadian FSAs

A Forward Sortation Area is the closest thing Canada Post has to a permanent address. Provinces, cities and street names churn constantly in the data — but the FSA layer is bedrock. Out of 1,678 FSAs seen across the whole period, only one ever disappeared, and it later reappeared. New ones arrive a handful at a time.

So what are the 42 arrivals? Almost none are brand-new neighbourhoods. They fall into three buckets. A minority are genuine delivery areas — fast-growing suburbs and exurbs that finally earned their own sorting code, like J5N Sainte-Anne-des-Plaines (Québec) or V4Y near Enderby, BC. A cluster are special "large-volume receiver" codes — single buildings and business blocks in downtown Toronto and Montréal, where the second letter is a tell-tale W, Y or Z. And the largest group is simply the rural and northern map filling in — sparse codes in Nunavut, the Yukon and back-country BC that the 2022 feed hadn't fully captured yet.

In other words, the FSA count creeping from 1,637 to 1,678 isn't 41 new places on the map. It's mostly the dataset catching up with places that were always there — the same signal-vs-noise story that runs through this whole project.

H4Z — the Tour de la Bourse (Montréal's stock-exchange tower) — is the only FSA ever to leave the file. It held a single code, H4Z 1A1, in 2022, then dropped out for the next five snapshots.

Then in February 2026 it came back — not as one code, but 33 of them. A special-purpose downtown block that had been quietly re-catalogued. Of 1,678 FSAs across six years, this is the entire story of "removals": one building, gone for three years, now bigger than ever.