Radnorshire was created in 1542 as a constituency of the House of Commons of the Parliament of England then of the Parliament of Great Britain from 1707 to 1800 and of the Parliament of the United Kingdom from 1801 to 1918. It elected one knight of the shire (MP) by the first past the post system.

Breconshire or Brecknockshire was a constituency in Wales which returned one Member of Parliament (MP) to the House of Commons of the English Parliament, and later to the Parliament of Great Britain and of the United Kingdom, between 1542 and 1918.