These are Scotland's only national landscape designation. They are those areas of land considered of national significance on the basis of their outstanding scenic interest which must be conserved as part of the country's natural heritage. They have been selected for their charachteristic features of scenery comprising a mixture of richly diverse landscapes including prominent landforms, coastline, sea and fresh water lochs, rivers, woodland and moorlands. NSA's were identified by the former Countryside Commission for Scotland and they are described in "Scotland's Scenic Heritage", published in 1978. No new areas have been identified since then. Most areas are in private ownership although the Forestry Commission has some sizeable land holdings. There are 40 NSA'a in Scotland covering 1 million hectares, which is 12.7% of Scotland.