metropolitan borough, metropolitan county of West Yorkshire, historic county of Yorkshire, northern England. The borough takes its name from Kirklees Hall (17th century), whose estate houses a small Cistercian priory (1155) and the reputed grave of Robin Hood. The borough extends from flat-topped and heather-clad gritstone moorland in the Pennines to more open, industrialized valleys. From Huddersfield, in the Colne valley, a metropolitan area sprawls into the Calder valley and north and east into the Spen valley. The metropolitan borough includes the towns of Holmfirth, Kirkburton, Mirfield, Heckmondwike, Cleckheaton, Dewsbury, and Batley, as well as a number of small rural villages. The borough developed as a centre of woolen textile manufacture during the 19th century, but other industries, such as engineering, supplanted textiles as the economic mainstay during the 20th century. Huddersfield is the borough's largest town and administrative centre. Area 158 square miles (410 square km). Pop. (2001) 388,576.