katastritunnus

Katastritunnus is the official cadastral identifier used in Finland to uniquely identify a cadastral unit, typically a land parcel, within the national cadastral register. The system is maintained by the National Land Survey of Finland (Maanmittauslaitos). Each katastritunnus corresponds to a defined geographic unit and serves as the primary reference for property boundaries, ownership records, and land-use planning. The identifier is used in property transactions, mortgages, taxation, and inter-agency communications, and it helps anchor maps and spatial data in the cadastre.

The structure of a katastritunnus generally includes a municipality code and a parcel number, with additional sub-unit numbers used in some contexts. Formats can vary between official documents and online services, but the key function is to provide a stable, unique reference to a specific parcel within the cadastre. Katastritunnus can change when parcels are split, merged, or redefined, and such changes are recorded in the cadastral register.

In practice, the katastritunnus appears on official documents, in cadastre-related online services, and within land records, linking to other identifiers and to cadastral maps. It is closely related to other property identifiers used in Finland, such as kiinteistötunnus, which facilitate cross-referencing across different registries and datasets. The system aims to ensure precise, legally enforceable identification of land parcels for administration, planning, and commerce.