Milecastle 42: A Roman Fortification on Hadrian’s Wall in the United Kingdom

Visitor Information

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Official Website: www.english-heritage.org.uk

Country: United Kingdom

Civilization: Roman

Remains: Military

History

Milecastle 42 is located along Hadrian’s Wall near the Pennine Way and Hadrian’s Wall Path in Haltwhistle, United Kingdom. It was constructed in the early 2nd century AD during the governorship of Aulus Platorius Nepos, under Emperor Hadrian. The site was built by the Roman Second Legion Augusta as part of a defensive frontier marking the northern boundary of Roman Britain.

The milecastle functioned as a fortified gateway through Hadrian’s Wall, controlling movement and housing a small garrison, likely around eight soldiers. Its position overlooks Hole Gap, a natural low point in the landscape that could have been vulnerable to incursions. This strategic location suggests the milecastle played a key role in monitoring and securing this section of the frontier.

Evidence from inscriptions shows the site remained in use into the late 2nd century AD. A reused tombstone found here was dedicated by Pusinna, widow of Dagvalda, a soldier from the 1st Cohort of Pannonians, indicating continued occupation or reuse beyond the initial construction phase.

In the early 20th century, quarrying threatened the remains of the milecastle and nearby wall sections. The site was placed under state guardianship in 1960, and conservation efforts took place between 1960 and 1973 to protect and preserve the surviving structures.

Remains

Milecastle 42 has a rectangular layout with internal dimensions of approximately 17.8 by 14.4 metres. The walls, about 2.8 metres thick, survive up to 1.4 metres high and are built from large stone blocks. The milecastle features a short axis design, typical of early Hadrian’s Wall milecastles.

The northern gateway was substantial and likely supported a tower above it. Circular sockets at the outer ends of the gate passages held iron pivots for double gates that opened inward. No internal buildings remain, probably due to soil erosion and exposed bedrock, which have removed much of the archaeological evidence inside.

Two inscribed stones were found on site. One is a dedication slab commemorating Emperor Hadrian and the Second Legion Augusta, confirming the builders. The other is a reused tombstone of a Pannonian soldier, showing later reuse of materials.

Milecastle 42 had two associated turrets serving as lookout posts. Turret 42A was destroyed by quarrying, while Turret 42B was located in 1912 and survives as a turf-covered platform about 0.5 metres high. Nearby sections of Hadrian’s Wall at Cawfields Crags remain well preserved, with some stretches standing up to 3 metres tall and defensive ditches visible on the lower ground approaches.