Administrative (pop., 2001: 569,660) and geographic county, part of the historic county of Yorkshire, northern England.
Its administrative seat is Northallerton. Prehistoric sites show evidence of a military Roman occupation. In the Middle Ages it was a peripheral region of England with numerous castles of the great landowning families. Monastic orders, including the Cistercian s, grew wealthy from sheep farming. The area played a significant part in the Wars of the English Civil Wars . The modern economy is mainly agricultural.