Geography of Sheffield (Totley Brook passes south of Totley and meets Old Hay Brook at Needham's Dyke). The Sheaf flows northwards to join the River Don near Blonk Street Bridge in the city centre. This lower section of the River Sheaf together with the River Don, between the present Blonk Street and Lady's Bridge, formed part of the perimeter of Sheffield Castle. Porter Brook's source is just inside the Peak District National Park, to the west of the city, at Clough Hollow, also near Ringinglow. From here it flows eastward to meet the Sheaf, at a point now located underneath Sheffield Midland Station.
Economy of Sheffield public, such as the Abbeydale Industrial Hamlet and the Kelham Island Museum. Northwest of the city lies Wortley Top Forge, which was a heavy ironworks of international renown. It is a site of historical and industrial importance, contributing to Sheffield's reputation for manufacturing high-quality, precision steel goods, though actually it is located within the boundaries of neighbouring Barnsley. This is a chart of trend of regional gross value added (GVA) of Sheffield at current basic prices published (pp. 240–253) by "Office for National Statistics" with figures in millions of British Pounds Sterling. The city spearheaded the knowledge advances which gave