Barnsley is a metropolitan borough of the metropolitan county of South Yorkshire, England. Its main town is Barnsley. The borough is bisected by the M1 motorway; it is rural to the west, and largely urban/industrial to the east. 68% of Barnsley's 32,863 hectres is green belt and 9% is National Park land, the majority of which is West of the M1. In 2004 it was estimated that Barnsley had 221,000 residents, nine tenths of whom live East of the M1. The borough was formed under the Local Government Act 1972, by a merger of the county borough of Barnsley with Cudworth, Darfield, Darton, Dearne, Dodworth, Hoyland Nether, Penistone, Royston, Wombwell and Worsborough urban districts, along with Penistone Rural District, part of Hemsworth Rural District and part of Wortley Rural District, all in the West Riding of Yorkshire.