Northumberland role in the Industrial Revolution from the 18th century on. Many coal mines operated in Northumberland until the widespread closures in the 1970s and 1980s. Collieries operated at Ashington, Bedlington, Blyth, Choppington, Netherton, Ellington and Pegswood. The region's coalfields fuelled industrial expansion in other areas of Britain, and the need to transport the coal from the collieries to the Tyne led to the development of the first railways. Shipbuilding and armaments manufacture were other important industries before the deindustrialisation of the 1980s. Northumberland remains largely rural, and is the least-densely populated county in England. In recent years the county has
Bieszczady County . As of 2006 its total population is 22,213, of which the population of Ustrzyki Dolne is 9,478 and the rural population is 12,735. Its average population density of 19.5 persons per square kilometre (50.5 per square mile) makes it the least densely populated county in Poland. The county includes the greater part of Bieszczady National Park ("Bieszczadzki Park Narodowy"), and of the Polish part of the UNESCO-designated East Carpathian Biosphere Reserve. Bieszczady County is bordered by Lesko County to the west and Przemyśl County to the north. It also borders Ukraine to the east and south. The county is