Lonehort Battery was built on the eastern end of Bere Island to protect the approaches to Berehaven Fleet Anchorage. The Battery was built between 1898 and 1902.
This battery contains a single 9.2-inch Mark 10 gun and two 6-inch QF guns, the same as Rerrin Battery. The whole battery complex is surround by a dry ditch with prepared trenches built to provide defensive fire. This is unique for the batteries on Bere Island. Plans shows that it was intended to built four caponiers in the dry ditch, for additional defence, but this does not appear to have been realised.