Totnes Castle, Devon

English Heritage.
This was a classic Norman motte and bailey castle, founded soon after the Conquest to overawe the Saxon town. A later stone shell-keep crowns its steep mound, and gives sweeping views across the town rooftops to the River Dart. The shell-keep wall is in a fair state of preservation, as can be seen in stock photos.
Apart from the view, there’s not a large amount of things to look at, but the circular shell keep itself looks rather iconic. You’d think that a castle on a high mound would be easy to spot, but if I remember correctly I had a lot of difficulty finding it, because the crowded old buildings block any view of it from street level. If you don’t have any luck with brown signs, find a good street map and track it down with that. The old centre of Totnes is not car-friendly so if you arrive by car it would be best to park it in a car park on the edge of the town centre and continue on foot. When I was last there, it was possible to drive up the length of the old high street and under the building that spans the street, but I really wouldn’t recommend it! Also, the exit from the top of the high street onto the ring road is hazardous, because of poor visibility and high-speed idiots.
Other EH castles are in the same area of South Devon.