urban area and metropolitan borough, metropolitan county of Merseyside, historic county of Lancashire, England. It lies in the industrial belt between Liverpool and Manchester. Coal pits were exploited in the locality in the 16th century, and local sand deposits led to the introduction of glassmaking in 1773. Glassmaking long dominated the borough's industrial structure, but there has been some diversification. Area 51 square miles (133 square km). Pop. (2004 est.) 176,700.