Blatobulgium was a Roman fort, located at the modern-day site known as Birrens, in Dumfriesshire, Scotland. It protected the main western road to Scotland.
It was one of the "outpost forts" outside the Roman Empire when the frontier was on Hadrian's Wall and was located about 11 miles from the Castra Exploratorum fort.
Wikipedia https://en.wikipedia.org/wiki/Blatobulgium
Address DG11 3, United Kingdom
Coordinates 55°3'54.003" N -3°13'27.835" E
