William Kerr, 6th Marquess of Lothian

William Kerr, 6th Marquess of Lothian, KT, FRSE (4 October 1763 – 27 April 1824), was a British soldier, landowner and politician.

Kerr was born on 4 October 1763, the son of the then Lord Newbattle and Elizabeth Fortescue.

When he was five he was the subject of several pictures with his sister, executed by Valentine Green as mezzotints for publication.

In 1786 he was elected a Fellow of the Royal Society of Edinburgh; his proposers were Dugald Stewart, James Hutton and John Robison.

He married, firstly, Lady Harriet Hobart,[4] a daughter of John Hobart, 2nd Earl of Buckinghamshire (and the divorced wife of Armar Lowry-Corry, 1st Earl Belmore), on 14 April 1793.