The Antonine Wall was, from AD154 to AD 162 and a few years after AD208, the northernmost frontier of the Roman Empire in Britain. Built of turf on a stone foundation, it was about 10 ft high and 16 ft wide, punctuated by string of 16 forts with small fortlets between them.
The interactive map on the Heritage Daily site gives detailed
information about each fort besides pinpointing its location in the
wall. More here.