When the administrative county of Lancashire was created by the Local Government Act 1888, Rochdale was elevated to become the County Borough of Rochdale and was, in modern terms, a unitary authority area exempt from the administration of Lancashire County Council. In 1900 most of Castleton Urban District was added to the borough; this urban district included parts of Castleton, Hopwood and Thornham townships. In 1933 parts of Norden Urban District and Birtle with Bamford civil parish were added to the borough. Under the Local Government Act 1972, the town's autonomous county borough status was abolished. The municipal boroughs of Middleton and Heywood and Littleborough, Milnrow and Wardle urban districts are now part of the Metropolitan Borough of Rochdale, one of the ten metropolitan boroughs in Greater Manchester.