Although Lord-Lieutenants were appointed to a few counties in Scotland from about 1715, it was not until 1794 that a royal Warrant ordered the development of volunteer forces for the defence of the country and permanent lieutenancies were established. Forces were based in each county led by a Lord Lieutenant who was appointed by the Sovereign and who in turn appointed Deputies. The duties included provision for the protection of their counties in the event of invasion, threat or civil uprising. They directed volunteer forces, and after the Militia Act of 1797, were empowered to raise and command county militia units. After 1802 the Lord-Lieutenant was an ex officio member of the Police Committee and the Local Authority but the Local Government Act of 1889 abolished these functions and the role of lieutenancies gradually became more ceremonial.

The traditional links with the military have however been preserved through the association with the Armed Forces, the Territorial Army and other Reserve and Cadet Forces. Strong links have also been developed with the emergency services and a wide variety of voluntary organisations. However the principal role of the Lord-Lieutenant is as the personal representative of His Majesty The King in the Lieutenancy area.

Previous Lord-Lieutenants of Ayrshire and Arran include: 

  • Archibald Montgomerie, 11th Earl of Eglinton, 1794 – 1796
  • Hugh Montgomerie, 12th Earl of Eglinton, 1796 – 1819
  • George Boyle, 4th Earl of Glasgow, 1820 – 1842 
  • Archibald Montgomerie, 13th Earl of Eglinton, 1842 – 1861
  • Archibald Kennedy, 2nd Marquess of Ailsa, 1861 – 1870
  • John Dalrymple, 10th Earl of Stair, 1870 – 1897
  • George Arnulph Montgomerie, 15th Earl of Eglinton, 1897 – 1919
  • Archibald Kennedy, 3rd Marquess of Ailsa, 1919 – 1937
  • Sir Charles Fergusson, 7th Baronet, 1937 – 1950
  • Sir Geoffrey Hughes-Onslow, 1950 – 1969
  • Sir James Fergusson, 8th Baronet, 1969 – 1973
  • Colonel Sir Bryce Muir Knox, 1974 – 1991
  • Major Sir Richard Yates Henderson, 1991 – 2006
  • John Lawrence Duncan, 2006 - 2017
  • Sheriff Iona Sara McDonald , 2017 - Present

For further general information please refer to "The Lord-Lieutenants and their Deputies" by Miles Jebb, published by Phillimore.