Aberdeen (George Gordon, 4th Earl of) (1784 – 1860). Aberdeenshire, Scotland. 2 cards. <1 MB. More..
  [Senate House MS901/3/1].

Aberdeen University. Aberdeen, Scotland. 20 cards. 2 MB. More..
  includes: University Library; University muniments; King's College; Marischal College [Senate House MS901/2/1].

Aberdeenshire. Aberdeenshire, Scotland. 1 card. <1 MB. More..
  includes: Banffshire [Senate House MS901/2/1].

Aberdour. Fife, Scotland. 2 cards. <1 MB. More..
  includes: Inchcolme aka Inchcolm Abbey [Senate House MS901/2/1].

Abergavenny (Henry Nevill, 3rd Marquess of) (1854 – 1938). Kent, England. 3 cards. <1 MB. More..
  [Senate House MS901/3/1].

Abergavenny (Marquess of). Kent, England. 6 cards. <1 MB. More..
  [Senate House MS901/3/1].

Aberlady. East Lothian, Scotland. 1 card. <1 MB. More..
  includes: Parish Church records [Senate House MS901/2/1].

Aberystwyth. Ceredigion, Wales. 57 cards. 5 MB. More..
  includes: National Library of Wales aka Llyfrgell Genedlaethol Cymru; University College Wales aka Aberystwyth University; Peniarth [Senate House MS901/2/1].

ABHBA. 4 cards. <1 MB. More..
  poss. Rev. Beaver Henry Blacker [Senate House MS901/3/1].

Abingdon. Oxfordshire, England. 19 cards. 2 MB. More..
  includes: Abingdon Abbey; corporation documents; Abingdon School; Christ's Hospital [Senate House MS901/2/1].

Abingdon (Countess of). Oxfordshire, England. 1 card. <1 MB. More..
  [Senate House MS901/3/1].

Abinger (James Scarlett, 1st Baron) (1769 – 1844). Surrey, England. 1 card. <1 MB. More..
  [Senate House MS901/3/1].

Abney, of Measham, Derbyshire. Leicestershire, England. 1 card. <1 MB. More..
  formerly Derbyshire [Senate House MS901/3/1].

Aboyne (Charles Gordon, 11th Marquess of Huntly, Earl of) (1847 – 1937). Aberdeenshire, Scotland. 1 card. <1 MB. More..
  [Senate House MS901/3/1].

"Abracadabra". 2 cards. <1 MB. More..
  [Senate House MS901/3/1].

Absalom (Philip). London, England. 1 card. <1 MB. More..
  of Lyon's Inn [Senate House MS901/3/1].

Account of the Executors of Richard, Bishop of London. England. 1 card. <1 MB. More..
  includes: "Account of the Executors of Richard, Bishop of London, 1303, and of the Executors of Thomas, bishop of Exeter, 1310" [Senate House MS901/2/18].

Achonry. Sligo, Ireland. 1 card. <1 MB. More..
  [Senate House MS901/2/1].

Achurch. Northamptonshire, England. 1 card. <1 MB. More..
  includes: Parish Church [Senate House MS901/2/18].

Ackton. West Yorkshire, England. 1 card. <1 MB. More..
  see also: Lupset, Yorkshire [Senate House MS901/2/1].