Hadrian’s Wall is the Roman frontier wall begun in AD 122 on the orders of Emperor Hadrian, running 73 miles (about 117 km, or 80 Roman miles) across northern England from Wallsend on the River Tyne to Bowness-on-Solway on the Solway Firth. It was never simply a barrier: 80 milecastles each guarded a gateway through it, 16 forts held a garrison of roughly 10,000 auxiliary soldiers, and the gates probably worked as customs posts where people, livestock and goods were checked and taxed. It lies entirely inside England and has never been the Anglo-Scottish border, though it is often loosely described that way. The best way to understand its geography is to follow it from east to west through the places where it met rivers, roads and people.
The builders were soldiers of three legions, the II Augusta, VI Victrix and XX Valeria Victrix, who completed most of the work in about six years. The eastern stretch was stone. West of the River Irthing, from Milecastle 49 to the Solway, the first version was stacked turf, later replaced in stone. Behind the curtain wall ran the Vallum, a broad ditch between two mounds, and between each pair of milecastles stood two turrets, 158 in all. Every crossing described below was built into that system.
Segedunum at Wallsend, where the line met the Tyne
The wall did not originally start at Wallsend. Hadrian’s first plan ended it at Newcastle, but around AD 127 it was pushed about 4 miles (6 km) further east, through what is now Byker, to a new fort called Segedunum. The extension was narrower than the rest, 7 feet 6 inches (2.29 m) thick, and it had no Vallum, because the River Tyne already did that job on the south side.
Segedunum measured 138 m by 120 m, about 4.1 acres, and was occupied from the 120s until almost 400. It is now the most thoroughly excavated fort on the whole line, and the town that grew over it carries the wall in its name. It is also the starting stamp of the Hadrian’s Wall Path, the 84-mile (135 km) National Trail opened in 2003, which is usually described east to west, although that direction walks into the prevailing wind.
Pons Aelius, the bridge that named Newcastle first
Four miles upstream, the Romans bridged the Tyne and built a small fort on the north bank to guard it. They called both Pons Aelius, the Aelian Bridge, after Hadrian’s family name, Aelius. It is the only bridge known to have been named after an emperor outside Rome. The fort sat where The Castle stands in central Newcastle today, at the northern end of Cade’s Road, which is thought to have run south to Chester-le-Street and York.
For all the imperial name, Pons Aelius was small: the fort covered about 1.53 acres, and its civilian settlement may have held around 2,000 people. Its value was the crossing. Anglo-Saxons later built over the site, and excavations between the 1970s and 1990s found more than 600 of their graves. The wall itself is still turning up beneath the modern city: in 2021 engineers from Northumbrian Water repairing a water main in central Newcastle uncovered a previously unknown 3-metre section and re-angled the pipe to leave it undisturbed.
The Portgate on Dere Street
North of Corbridge the wall crossed the most important road in the north. Dere Street, the main route from York into the lands beyond, was about 50 years older than the wall, so the frontier had to accommodate it. The answer was the Portgate, a fortified gateway of very large masonry blocks that sat astride the wall and projected some 3 to 3.7 m north of it. Its remains now lie under a stub of the old B6318 Military Road just south-west of the Stagshaw Roundabout.
The Portgate matters because it shows what the frontier was for. Two kilometres north along Dere Street, near Great Whittington, archaeologists have found a concentration of Roman-period metalwork and mostly silver coins, pointing to high-value exchanges just outside the gate. The coins thin out in the decades when the garrison moved north to the Antonine Wall and pick up again once it came back. South of the gate stood Corstopitum, modern Corbridge, an arsenal and supply centre far larger and more populous than Pons Aelius. Elsewhere Roman coins and pottery rarely crossed the wall at all, so gates like this one were where contact was allowed to happen.
Chesters Bridge over the North Tyne
At Chollerford the wall had to cross the North Tyne, and the Romans built at least two bridges there, next to the cavalry fort of Cilurnum, now called Chesters. The first, built around AD 122 to 124, stood on at least eight hexagonal stone piers roughly 4 m apart and spanned 61 m. Its piers were sized for a structure 10 feet (3 m) wide, which suggests it carried the wall itself across the river on a line of small arches.
The second bridge, built later (dates proposed range from the 160s to the early 3rd century), was a road bridge for the Military Way, the service road behind the wall. It had four arches on three river piers set 10.4 m apart and was 57.6 m long. The river has since shifted about 20 m west, burying or sweeping away the west abutment and leaving the eastern one stranded on the bank. The remains were first identified in 1860, and public access to them was suspended in 2016 after flood damage.
Housesteads and the Whin Sill, where crossing was hard
West of Chesters the land rises to the Whin Sill, a hard ridge of dolerite whose north face breaks into cliffs. Here the wall runs along the crag edge, and the natural drop did much of the defending. Housesteads fort, the Roman Vercovicium, sits at the end of a mile-long crag, 5.3 miles west of Carrawburgh and about 2 miles north-east of the older fort of Vindolanda on the Stanegate road. It was built in stone around AD 124 on top of the foundations of a demolished turret, Turret 36B, after the plan changed to put forts on the wall line.
About 3 km further west, between Milecastle 39 and Crag Lough, the wall dips into Sycamore Gap, a notch cut by glacial meltwater. The sycamore that stood there for more than a century became one of the most photographed trees in England until it was illegally felled in 2023; the two men responsible were each jailed for 4 years and 3 months in July 2025, and the stump has since sprouted new shoots. The gap shows how the builders handled terrain: rather than skirt the dips, the wall plunges down and climbs out of each one.
The Military Road, the B6318, runs close to this stretch. General Wade’s engineers built it after the Jacobite rising of 1745, taking much of the wall’s stone for the roadbed. What survives here owes a great deal to John Clayton, the Newcastle town clerk who from 1834 bought up the land between Brunton and Cawfields, including Housesteads, to stop farmers carting the stones away.
Birdoswald and the River Irthing crossing
The fort of Banna, now Birdoswald, stands on a triangular spur above a broad meander of the River Irthing in Cumbria. It was built to protect the crossing where a Roman bridge carried the wall over the Irthing at about the same time the wall was built. This is also where the construction changes: the Irthing marks the point west of which the first wall was turf rather than stone, and Birdoswald’s first fort, around 125, was turf and timber before being rebuilt in stone around 130. The longest surviving continuous stretch of the wall runs from the fort, and the site stayed in use long after Rome, becoming a farm that operated until 1984.
Stanwix, the Eden and the Solway shore to Bowness
At Carlisle the wall crossed the River Eden. On the north bank, within sight of the older fort of Luguvalium in the town, stood Uxelodunum, now buried under the suburb of Stanwix. It was the largest fort on the wall because it housed the Ala Gallorum Petriana, a nominally 1,000-strong cavalry regiment and the only one of that size in Britain. Carlisle and Corbridge were the two river-crossing forts that the earlier Stanegate road had linked, and the wall was laid out slightly north of that road.
Beyond Carlisle the wall ran along the southern shore of the Solway estuary through Burgh-by-Sands (Aballava) and Drumburgh (Coggabata) to Maia at Bowness-on-Solway, the second-largest fort on the line. A 2nd-century bronze pan found in Staffordshire in 2003 lists four of these western forts in order, MAIS, COGGABATA, VXELODVNVM and CAMBOGLANNA, above the words taken to mean “Hadrian’s Wall”; it was probably a soldier’s souvenir. The wall ended a short, unknown distance west of the village, but the frontier did not: milefortlets and towers linked by a timber palisade continued down the Cumbrian coast as far as Risehow, south of Maryport, to watch for crossings by sea.
Bowness has had its own crossings since. In 1869 the Solway Junction Railway opened a 1.1-mile iron viaduct across the firth to Annan in Scotland; ice floes wrecked large parts of it in 1881. A small pavilion on the shore now marks the western end of the National Trail.
How long the crossings stayed in use, AD 138 to 410
The wall’s working life was not continuous. After Hadrian died in 138, Antoninus Pius moved the frontier about 160 km north to the turf Antonine Wall across central Scotland, leaving Hadrian’s line in a support role. Under Marcus Aurelius the army pulled back and reoccupied Hadrian’s Wall as the main frontier, and Septimius Severus campaigned in Caledonia between 208 and 211 before the Romans again withdrew to it. It stayed garrisoned until Roman rule in Britain ended around 410, and some forts were occupied into the 5th century.
Hadrian’s Wall was listed as a UNESCO World Heritage Site in 1987 and became part of the transnational Frontiers of the Roman Empire site in 2005, alongside the German frontier. For how it fits into the wider map of Rome’s boundaries, see our guide to the geography of the Roman Empire; in 2018 its managers signed a cooperation agreement with those of China’s wall, whose route is traced in the Great Wall of China as a border, and the pair sit among the many barriers compared in our look at border walls around the world.