The Howardian Hills has a complex geology, dominated by Jurassic limestone. The structure of the bedrock has resulted in steep ridges and varied soil types. During the last ice-age the deeply incised Kirkham Gorge was formed, which is of great scientific importance.

The landform consists of an intricate network of ridges, hills and valleys. These are clothed with a mosaic of woodland, rolling arable fields, small-scale pasture, fens, hedges and walls, formal parkland and scattered settlements.

The River Derwent, which flows through the eastern Howardian Hills, is nationally significant for its unusual geomorphology and outstanding wild plants and animals. Other habitats of national importance include fens and significant remnants of Ancient Semi-Natural Woodland.

The Howardian Hills has a concentration of archaeological and historic features, ranging from Iron Age earthworks on prominent hilltops to the castles and monasteries of the medieval period. The numerous grand houses and designed landscapes have a dramatic effect upon the scenery.