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
Essex County, New Jersey Based on data from the 2010 census, Essex County is the 14th-most densely populated county in the United States, and was ranked second in the state after Hudson County (which ranked sixth in the nation at 13,731.4 per square mile). Newark, with a population density of 11,458.3 people/square mile, is the largest municipality in the county both in terms of land area (24.19 square miles) and population (277,140), while Caldwell is the smallest in terms of land area (1.17 square miles) and Essex Fells has the smallest population (2,113). Many of the county's smallest municipalities have population densities that are