Around Haltwhistle the wall country becomes the landscape everyone imagines: the Whin Sill, a long ridge of hard volcanic dolerite, rears up in a series of cliffs facing north, and the Romans used it as a ready-made rampart, running their stone wall along the very top. Between the crags and the road the vallum ditch runs across the fields as a broad, clear trench, and from any high point you can see the whole military system laid out: crag, wall, road and ditch side by side.
Walltown Crags, a few miles east of here, has some of the highest-standing wall on the whole frontier, climbing and dropping along the ridge in a way that looks almost impossible to build. Close by, at Carvoran, the Roman Army Museum explains how the garrisons lived, and Thirlwall Castle, a fourteenth-century tower built from Roman stone, stands ruined above the Tipalt Burn. Vindolanda, further east, is where the famous wooden writing tablets were found, including a birthday party invitation from one commander's wife to another.
The riding is superb. The B6318 Military Road is straight in plan but heaves up and down over the ridges like a wave, with blind crests that hide oncoming cars, so hold back a little and do not trust the far side. There are no hedges, the views go for miles and the wind can be strong and gusty on the exposed tops. Sheep wander freely in places. The A69 in the Tyne valley to the south is the faster, duller alternative. In summer, walkers' cars cluster around the car parks; on a weekday in May or September the road is wonderfully empty.
Haltwhistle, which proudly claims to be the centre of Britain, is a small stone town with a fuel station, a few cafes and pubs and a supermarket; it is your nearest reliable supply, as the Military Road itself has almost nothing. Hexham with its abbey is the bigger town further east. Weather can turn from sunshine to horizontal rain in the time it takes to put on gloves, so pack accordingly, and be careful on the wet cattle grids.