Carrigadrohid . . . from the Irish . . . 'Carraig an Droichid'; literally, 'The Rock of the Bridge'.
The present day bridge is out of the picture behind this impressive castle ruin; the castle itself is built on a rock in the middle of the river, which is the Lee, eventually flowing through Cork city. This would have been an even more important river-crossing in the distant past. When I commenced taking this picture, there was much less water in the foreground area, but I noticed it was rising reasonably rapidly, and then becoming like a mini tsunami! I guessed it had to do with openng a sluice further upstream, which was confirmed later, when I spotted a WARNING sign to this effect on the bridge itself!
Historical info on next image.