Clarence Battery was originally called Terrest Point Battery when built in 1780. It was named Clarence Battery in 1815 and was located on the shoreline below Fort George. It was one of the principal coastal defence batteries covering the approaches to the harbour of St Peter Port. Initially armed with smoothbore guns with emplacements covering three sides. It had a walled enclosure, magazines and stores.
Plans from June 1853 show the battery has a total of ten guns, five facing North, four facing South and a single heavy gun on the apex with a 300 degree angle of fire (TNA MPHH 1/679).