Before the Acts of Union 1707, the barons of the sheriffdom or shire of Ayr elected commissioners to represent them in the Parliament of Scotland and in the Convention of the Estates. After the Union, Ayrshire returned one Member of Parliament to the House of Commons of Great Britain and later to the House of Commons of the United Kingdom.
List of shire commissioners
References
Ayrshire (Parliament of Scotland constituency) Wikipedia(Text) CC BY-SA