At the moment the old Sheffield markets are being removed. There were a couple of locations in the market where you could see the remains of the old Sheffield castle, one was easy to get to and the other was quite hazardous. At one stage you could see part of the castle down Castlegate, but I think this has since been embedded in a concrete structure, hopefully to protect. There was a archaeological dig done of the site before the castle markets where built back in the 60/70’s.
Once the castle market has been removed, there will be an archaeological dig of the site. I understand that there maybe quite a lot of the castle remaining, a quarter of the original gate house is still remaining and will be rebuilt.
A Park will then be built on the site of the old castle to show the remains that are uncovered. The River sheaf is embedded in concrete at this point and will be uncovered. At one stage Sheffield castle was bordered on one site by the river Don and the other by the river Sheaf.
People see Sheffield as being quite a modern city, that originated during the Industrial revolution, but that is not quite true as Sheffield castle was probably the biggest in the North, larger than that of York.
These are exciting times in Sheffield, as far as I am concerned.
All the best