On the eastern edge, the River Derwent cuts through the Hills in the Kirkham Gorge, a deep winding valley formed as an overflow channel from glacial Lake Pickering.

[4] The majority of older buildings are made of locally quarried limestone with red pantile roofs and those which developed as part of the grand country house estates have largely retained a coherent identity.

High grade arable land, pasture, and managed woodland makes this rich farming country whose diversity contributes to its attractive rural character.

[1][5] The Howardian Hills AONB is a key area for several nationally important Biodiversity Action Plan (BAP) Priority habitats including lowland broadleaved woodland, wood pasture, veteran trees, limestone, and neutral grasslands and fen meadows.

The Howardian Hills are designated an AONB because of the following Special Qualities: Each of these attributes is important in its own right, but it is their combination in a relatively small area that has produced a landscape of national significance.