A short way from the start at Market Cross lie the ruins of the castle, high above the foaming River Tees. The castle dates from the 12th century and the oldest standing section is Balliol Tower, built from sandstone over 700 years ago. Its name comes from its founder, Guy de Balliol, Lord of Bailleau in France. His successor Bernard de Balliol gave the town its name.

The castle itself, once one of the largest castles in England, has a long and turbulent history. For a time, it was home to Warwick the Kingmaker, who met his death at the Battle of Bosworth Field in 1485. During the Middle Ages, servants from the castle were allowed to graze their animals on common ground known as Desmesnes.

Abbey Bridge, at the south-east end of the walk, with its magnificent balustrade, was built in 1773. County Bridge (Bridgegate), spans the River Tees below the castle. A bridge has forded the river here for nearly 700 years. A small chapel used to stand in the middle of the bridge where eloping couples were married.

Downstream of County Bridge there used to be woollen mills and carpet factories, as well as the workshops of glove makers, tanners, stocking makers and dyers along the river banks. During the 19th century these were all very successful industries and many fine Georgian buildings testify to the prosperity of the area.

Egglestone Abbey is reached after crossing Thorsgill Beck by Bow Bridge, a cobbled 17th century packhorse bridge. The abbey, now in ruins, was founded in 1190. Henry VIII dissolved the monastery in 1536, though the original and later buildings are still visible. The abbey stands in glorious surroundings. The site buildings are protected as a Scheduled Ancient Monument and they are maintained by English Heritage, and admission is free.

Back in Barnard Castle and beyond the river stands the Bowes Museum, which was opened by John Bowes and his wife Joséphine Benoîte Coffin-Chevallier in 1892 to house fine art objects they collected throughout their philanthropic lives. The collections on show include early works of French glass maker Émile Gallé which were commissioned by Joséphine. A great attraction is the 18th-century Silver Swan automaton, which periodically preens itself, looks round and appears to catch and swallow a fish.

It is a short walk from the Bowes Museum back to the starting point of the walk at the Market Cross. This octagonal building has been a town hall and a gaol (prison). Nearby is Blagraves House, one of the oldest buildings in the town.