These milefortlets and intervening stone watchtowers extended from the western end of Hadrian's Wall, along the Cumbrian coast and were linked by a wooden palisade.

Milefortlet 13 was situated on the coast between the villages of Blitterlees and Beckfoot, in the civil parish of Holme Low.

[2] Each milefortlet had two associated towers, similar in construction to the turrets built along Hadrian's Wall.

[3] The foundations of the tower were found, and were 3.75 metres square internally.

[3] The site of Tower 13B is located in a field on high ground, and was excavated in 1880.