For most of the period this constituency was under the patronage of the Douglases, dukes of Queensberry. The interest of the Johnstone family, powerful in the earlier part of the century, was dormant after 1748, when the Marquess of Annandale, the head of the family, was declared insane and incapable of managing his affairs; it was revived towards the end of our period by a junior branch of the family, the Johnstones of Westerhall.

The 4th Duke of Queensberry, who succeeded in 1778, lived mostly in England and was unpopular in Scotland. At the general election of 1784 his interest in the constituency was challenged by three candidates: Sir James Johnstone of Westerhall; Sir Robert Herries, the sitting Member, whom Queensberry had discarded; and Alexander Fergusson of Craigdarroch. Queensberry’s candidate was his friend George Augustus Selwyn, who did not appear at the election, and as an Englishman, with a borough of his own, was hardly a suitable candidate. Dumfries and Lochmaben burghs declared for Johnstone; Kirkcudbright for Fergusson; Annan for Herries; and Sanquhar for Selwyn. Selwyn petitioned, alleging that the votes of Dumfries and Lochmaben were invalid and that he should have been returned on the casting vote of Sanquhar, the returning burgh. But he did not proceed with his petition.1