There were three castle place-names mentioned in the 1626 Rochdale Manor Survey, but I found the site before I knew of the reference to it.
We commissioned a geophysical survey and Al Oswald of English Heritage identified a strip lynchet on one of the site’s steep slopes (west facing).
It was not actually in Rochdale, it is in what was the old parish of….Middleton, in Ashworth township.
Copped Hill (facing North)
See the map/aerial view
Select “Satellite” to see an aerial view instead of the map.
“Have looked at data we have on Copped Hill. I’m vaguely remember the
location. I’m pretty sure I never went to the top of the hill. Maps I
did at the time show it has melt water channels on western and southern
sides. The hill is capped by sand and gravel which would have provided
a better drained/dryer site if it was chosen as settlement location.”
Dick Crofts – British Geological Survey 2008/12/03