tonttijaon

Tonttijaon is a Finnish term for the formal subdivision of land into building plots (tontit). It is a technical and legal process used to implement municipal land-use plans, define property boundaries, and create plots that can be sold, developed or otherwise managed according to planning regulations.

In practice tonttijako follows an approved detailed plan (asemakaava) or other planning decision. The procedure typically involves surveying, mapping, drafting a division proposal, and defining public areas such as streets and utility corridors. Professional surveyors prepare the measurements and plans, and the division is confirmed by the competent authority—municipal bodies in cooperation with the National Land Survey of Finland (Maanmittauslaitos) and recorded in the national cadastre (kiinteistörekisteri).

Legal and administrative rules governing tonttijako are part of the Land Use and Building Act and related regulations. The division determines parcel identifiers, exact boundaries, easements and rights of way, and may affect land-use obligations and building rights. It also clarifies responsibilities for infrastructure and maintenance of public areas.

Tonttijako serves to translate planning policy into enforceable property units, ensuring that development complies with zoning, environmental and technical requirements. Similar subdivision processes exist in other countries, but the term tonttijako is specific to Finland and its cadastral and planning system.