When it is completed, the initial inventory of heritage sites worthy of protection (ISOS) will contain around 6000 heritage sites located in the almost 3000 Swiss municipalities. The ISOS incorporates all of the towns, villages and hamlets in Switzerland.

It contains comparable site records and provides a basis for:

• planning at national, cantonal and municipal levels and
• monument and heritage protection as a decision-making basis in the conservation of neighbourhoods or individual buildings.

The ISOS is based on the Federal Act on the Protection of Nature and Cultural Heritage (NHG). Under this legislation, the federal authorities are obliged to take suitable account of the inventory in the fulfilment of their tasks.

If there are grounds for the assumption that an ISOS object could be affected as a result of intervention arising from a federal task, the relevant authority must request a report from the FCNC.