There is a lot of material on Totnes Castle from many sources; a Norman motte and bailey castle, it dates from around the 11th century following the Norman conquest. In the 13th and 14th centuries the castle was remodelled from a wooden surround on earth/ rock/ clay to a stone shell keep.
Today the castle is maintained by English Heritage. The ditch which originally surrounded the castle has been filled with cottages but there are still fine views from the castle across the town and down to the River Dart.
To find the castle walk up the High Street. Castle street leads off to the right, shortly before the road bears to the left. Walk down Castle Street, a short way, and the castle is on your left.
Totnes castle is now owned by English Heritage (http://www.english-heritage.org.uk/server.php?show=conProperty.317)