Situated on a promontory, commanding the River Dart, Totnes Castle was built by the Normans at a point where three valleys meet. Earliest surviving parts of Totnes Castle date from the 11th century, in the form of earth works surrounding the site, with a later motte and bailey castle being constructed on the built-up earthworks. The stone work of Totnes Castle that has survived is likely to have been built over the framework of previous timber fortifications, as was common practice of this period.
During the 13th century the large, circular shell keep was built on top of the motte, but was reconstructed at the beginning of the 14th century when other renovation work was carried out, including the rebuilding of the entrance arch and stairways within the thickness of the walls. Some small-scale additional work took place at a later date. This circular stone keep stands to parapet height even today, and remains almost complete with the various shaped arrow slits visible around the top. Moreover, within the shell keep, stone foundations of a square tower have also survived.
Externally, a ditch separates the keep from the inner bailey. Although at one time this completely encompassed the motte, parts have now been filled in. The curtain wall around the inner bailey has largely disappeared, along with the domestic buildings contained within it, save for a few of the original foundations. Further protection was afforded to Totnes Castle by a moat, although again this been filled in over the years. Beyond the moat, an outer bailey would have provided farmland for Totnes Castle rather than any additional protection.
Despite little remaining of the original motte and bailey castle, other than the earthworks, the stone enclosure of Totnes Castle's keep, built at the summit of the motte, has survived to the extent of being one of the best preserved in England.