The picturesque town of Barnard Castle stands over the waters of the River Tees, which used to form the boundary between Durham and Yorkshire until 1974. The remains of the castle, which was built in the early 12th century, still tower over the river. Down below, the bridge, which was built in 1569, is still the main route over the Tees. The town dominates the roads into Teesdale and into the uplands of the North Pennines, but is also close to the Victorian industrial city of Darlington.
There is no evidence for archaeological remains from the earliest periods of prehistory. It is only in the Bronze Age (2300BC to 800BC) that the first evidence for prehistoric activity is seen in the area. A Bronze Age (2300BC to 800BC) burial {urn D1936} was found at an unknown site in the town in the 19th century. Other Bronze Age objects include two spearheads, one found at {Barnard Castle School D1943} in 1951, and the other found on the banks of the River Tees in 1974. Although these objects suggest some kind of activity in the area no evidence for settlements of this date have been found in the parish. This is not because people had not settled the region, but because the remains of their homes and villages are very slight, which make their discovery by archaeologists difficult. The same problem is true also for the Iron Age (800BC to AD43). The only known remains from this period are two {necklaces D1942} made from twisted gold wire. These were rediscovered in 1873, and are now in the British Museum.

There are no remains of any Roman (AD43 to 410) buildings in Barnard Castle, but it is likely that there was some kind of small settlement near the bridge. Many {Roman coins D1986} have been found in Bridgegate. This close to the ford where the {road D4116} from Bowes to Binchester crossed the River Tees.
Several pieces of pottery have also been found nearby in {Newgate D1993}. Galgate, at the top of the market place, follows the line of the same road.

Although Anglo-Saxon (AD410 to 1066) occupation is well recorded in southern Durham no traces of this period have been found here. Unlike many other nearby churches there is no sign of any carved stone crosses associated with the church. This is because the town of Barnard Castle, as its name suggest, grew up around the medieval castle. There was no earlier Anglo-Saxon settlement on the site.

The medieval history of the town is dominated by the {castle D1970} and the Balliol family who owned it. The castle was built in the late 11th century. Bernard Balliol gave land to the townsfolk and the market in the town was established. When the castle was built it outer defences may have surrounded the small church of St Margaret, which was probably the parish church. A new parish church, dedicated to St Mary was built outside the walls. It was not the only religious establishment in the town. In around 1230 a {small hospital D1937} was founded on Newgate Street. It had its own {chapel D1938}. An {Augustinian friary D1974} was also founded in the town in the late 14th century.

During the reign of Queen Elizabeth I Barnard Castle was involved in the Rising of the North, a rebellion against the monarchy. This revolt was defeated and its leaders executed. Because of their support for the Rising the people of the town had to be in their houses each evening by 8pm. This was signalled by the ringing of a bell. This tradition continued until the mid 20th century.

Most of the buildings along the main roads of the town date to the post-medieval period (1540 or later). In the main street stands the Butter Market built in 1747. This used to be the administrative headquarters of the town. Nearby is the King's Head hotel where Charles Dickens stayed whilst collecting material to write Nicholas Nickleby.

In the 18th and 19th century, as well as being a centre for the surrounding farms Barnard Castle also supported a number of small industries such as Thorngate Mill.

During the First World War a number of the buildings and their associated outbuildings along Galgate, Horsemarket and the Market Place were used for military purposes including billets and stables whilst a Durham Militia barracks was established on Wilson Street as the HQ of the 4th (Special Reserve) Battalion Durham Light Infantry. Many of the local churches contain war memorials in the form of Rolls of Honour, books of remembrance and plaques dedicated to individuals from the local area who fought and died in the conflict. The town memorial monument and a memorial dedicated to the Durham Light Infantry can be found in the grounds of the Bowes Museum.