Stonefield Castle is a Scottish baronial manor house near the village of Stonefield, north of Tarbert. It was built on the site of an earlier building, known as Barmore, and has been in use as a hotel since 1950.
The original house of Barmore was constructed by the MacAlister family, who held nearby Tarbert Castle as tenants of the Duke of Argyll. They built the new house in the early 18th century, as the castle was deteriorating. Prior to this, Archibald Campbell, Sheriff of Argyll, had purchased the Barmore estate from Archibald MacAlister of Tarback in 1746.
The present castle was commissioned by John Campbell (1788-1857), grandson of John Campbell, Lord Stonefield (1720–1801), and designed by Edinburgh architect William Henry Playfair. It was completed in 1837, replacing the earlier Barmore. Playfair designed a number of buildings in the grounds, including bridges and a folly, and may have advised on the layout of the gardens.
Campbell planted a number of species of Rhododendron and Magnolia, using seeds recently acquired on botanical expeditions. The plant collections were maintained and enhanced by later generations of Campbells, who also had gardens at Achnacloich near Connel.
In 1948, the Campbells sold Stonefield, and it opened as a hotel in 1950.
The castle is a category B listed building and the grounds of the house are included in the Inventory of Gardens and Designed Landscapes, as an "important example of a 'west coast' woodland estate landscape" of national importance, with an outstanding plant collection.