 During the Roman period, the coast around present-day Blitterlees was fortified, as a series of milefortlets were built along the Solway plain, extending beyond the western end of Hadrian's Wall.The closest milefortlet to the settlement was milefortlet 12, which was originally constructed of earth and timber.In the 19th century, the name was spelled Blitter Lees, with a space between the two words.