Ross and Cromarty, also referred to as Ross-shire and Cromartyshire, is a variously defined area in the Highlands and Islands of Scotland. There is a registration county and a lieutenancy area in current use, the latter of which is 8,019 square kilometres in extent. Historically there has also been a constituency of the Parliament of the United Kingdom, a local government county, a district of the Highland local government region and a management area of the Highland Council. The local government county is now divided between two local government areas: the Highland area and Na h-Eileanan Siar. Ross and Cromarty border Sutherland to the north and Inverness-shire to the south.

The shires of Scotland, or counties of Scotland, are historic subdivisions of Scotland established in the Middle Ages and used as administrative divisions until 1975. Originally established for judicial purposes, from the 17th century they started to be used for local administration purposes as well. The areas used for judicial functions (sheriffdoms) came to diverge from the shires, which ceased to be used for local government purposes after 1975 under the Local Government (Scotland) Act 1973.