Castlegate is one of eleven Quarters in Sheffield's City Centre. It is now bound by Commercial Street and part of the High Street to the south, Exchange Place to the east, the road named Castlegate to the north, Angel Street and Snig Hill to the west. Castlegate is the main thoroughfare to and from the North of Sheffield as it links Park Square to The Wicker, although it is intended that the Sheffield Northern Relief Road will take this traffic when completed, allowing Exchange Place, Castlegate and The Wicker to be downgraded. Castlegate, built along a portion of the River Don, was the old location of the slaughter houses. It also served as a back entrance to the Alexandra Opera House as well as the market quarter situated on the site of the former castle of Sheffield, hence the name of the street and quarter.