Milefortlet 4

Milefortlet 4 (Herd Hill) was a Milefortlet of the Roman Cumbrian Coast defences. 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. They were contemporary with defensive structures on Hadrian's Wall. There is little to see on the ground but Milefortlet 4 has been located by archaeologists.

• http://en.wikipedia.org/wiki/Milefortlet 4