The Romans had such forts all over the Empire. The Roman legions maintained the frontiers, and maintained public order when needed in Roman cities.
Contrary to the anachronistic and generally nationalistic modern claims, Britain was hardly any trouble for the Romans, which is why it was part of the Empire for such a long time. One of the splinter empires during the Crisis of the Third Century was based in Britain.
The most common claim (at least here on FR) is that the Romans were never able to conquer Scotland — which is true, but only because the Scots hadn’t entered Caledonia, and didn’t get there until the 6th c. Prior to that they lived in Ireland. The Romans realized early on that there was literally nothing of any value to them in Caledonia.
Hadrian’s Wall was constructed (for the most part) along the top of a natural feature. The Romans used it to keep the occasional band of brigands from raiding the settled province. It also served as a way to collect the modest taxes from cross-border trade.
The last large Roman expedition north of the wall was by Septimius Severus, and was in response to various problems the friendly neighbors north of the wall having been under attack by raiders. It’s not unlikely that the massive defeat of the Caledonians at that time led eventually to the early medieval Viking raids and settlements in the far north.
The Severan Dynasty and/or its collapse led to and/or contributed to the Crisis of the Third Century.
Severan Dynasty...grandson Elagabus, the decadant "New Age" emperor.