The Tower of Hallbar was built in response to a 1535 Act of Parliament directing those with land to the value of 100 pounds in the area to construct a tower, thirty-foot square, to protect his household from the English Border raiders.

The first mention of Hallbar ('bar' - Gaelic for height, therefore 'high' hall) is in an Act of Parliament in 1581 ratifying the transfer of the Barony of Braidwood to Harie Stewart of Gogar, brother of the Earl of Arran.

Hallbar rises four storeys to the 19th-century battlemented parapet and a second floor garderobe was also added in the Victorian period. The interior, before conversion, consisted of five rooms, one above the other. The cellar was probably used for storage or as a cattle refuge in time of attack. The dog-leg staircase contained within the wall is unusual compared to similar towers which have spiral staircases.