Glenblocker fort

The term, Glenblocker fort, sometimes also called the Highland line fort is used to describe members of a line of Roman forts along the Highland Line in Scotland. The forts all share the common characteristic that they are close to the mouth of a glen (a narrow valley) or a strath (a broad valley) and can thus supervise traffic.

All of the forts were originally built during the Flavian occupation in Scotland. The group consists of
 * Drumquhassle (near Drymen) overlooking the southern end of Loch Lomond and the road back to the Clyde).
 * Malling (on the Lake of Menteith, overlooking the access to the Duke's Pass and a narrow point between the mountains and the Forth Mosses)
 * Bochastle (near Callendar), overlooking the road to Loch Katrine and the Pass of Leny
 * Dalginross (near Comrie) overlooking the Eastern end of Loch Earn
 * Fendoch (north of Crieff) overlooking the Sma' Glen
 * Inchtuthil, (below Dunkeld) The legionary fortress at the mouth of Strath Tay, guarding the main roads to Inverness
 * Inverquharity (near Kirriemuir) a fortlet-sized station at the east end of Glen Clova

It is debatable, whether Cardean, Stracathro and Doune should be listed among these, as they are sited further away from their respective traffic corridors, but fulfill the same function.

It has traditionally been thought that these forts were meant to prevent invasions out of the Scottish Highand into Roman held territory. This is ultimately probably their aim, but they were never meant to operate in isolation but in cooperation with the other forts on the Gask Ridge and along Strathmore, as only the legionary fortress of Inchtuthil with 5000-6000 soldiers would have been strong enough to deal with a major incursions. The smaller forts are more likely to serve as a disincentive to small scale raiding parties etc.,