Castlefield is an inner city conservation area of Manchester in North West England. The conservation area which bears its name is bounded by the River Irwell, Quay Street, Deansgate and the Chester Road. It was the site of the Roman era fort of Mamucium or Mancunium which gave its name to Manchester. It was the terminus of the Bridgewater Canal, the world's first industrial canal built in 1764, with the oldest canal warehouse opening in 1779.