The BFS number — a municipality's real name

If you had to identify a Swiss municipality beyond any doubt, you might reach for its name or its postal code. Both let you down. Names are reused across cantons and get changed after mergers; postal codes belong to the post office and can be shared or moved. The identifier that actually holds still is the BFS number — a stable code the Federal Statistical Office (Bundesamt für Statistik, BFS) assigns to every one of Switzerland's 2'123 municipalities.

Why the name isn't enough

Municipality names are not unique. The same name recurs in different cantons, which is why registers add a canton suffix — "Moiry" in Vaud has to be told apart from its namesakes. And after a merger a familiar name can disappear from the official list entirely. A name is how humans read a municipality, not how you identify one.

Why the postal code isn't enough

A postal code is a delivery key, not an identity — the point of a postal code is not a municipality. A single code can be shared by several municipalities, so it can never pin down exactly one.

What the BFS number does

The BFS number survives renamings and, for a surviving municipality, stays fixed. That is precisely why it is the join key behind every dataset on this site: population, tax multipliers, federal vote results, National Council elections and climate figures all come from different agencies, and the BFS number is what lets us line them up onto the same municipality without guessing from names.

When municipalities merge, the new entity is issued its own number and the old ones are retired — the mechanism behind why the number of municipalities keeps falling. For how it all fits together, see how Swiss addresses are structured.