Borough constituencies are predominantly urban while county constituencies are predominantly rural. There is no definitive statutory criterion for the distinction; the Boundary Commission for England has stated that, "as a general principle, where constituencies contain more than a small rural element they should normally be designated as county constituencies. Otherwise they should be designated as borough constituencies." In Scotland, all House of Commons constituencies are county constituencies except those in the cities of Glasgow, Edinburgh, Aberdeen, Dundee and three urban areas of Lanarkshire.