O'Ferrall's Linea Antiqua Vol. 1 (Betham Collection), [ca. 1808-1853].

Genealogical abstracts of Prerogative wills, approximately 1530-1800, compiled by Sir William Betham, New Series Volume 9: D, 1810.

Pedigrees of Irish families compiled by Sir William Betham, with index, [early 19th century].

Diary of business done in the Ulster's Office, 1777-1799 with cash account kept by William Betham, 1807-1809, 1777-1799; 1807-1809.

Betham Red Books 2nd series: Papers relating to the arms and pedigrees of various families compiled by Sir William Betham, Volume 3, [n.d., between ca. 1820 and 1850].

The Gael and Cymbri :

or, An inquiry into the origin and history of the Irish Scoti, Britons, and Gauls, and of the Caledonians, Picts, Welsh, Cornish, and Bretons /

Collection of pedigrees of Irish families in the hand of Sir William Betham with copies of transcriptions of records, deeds, inquisitions, patents, etc., compiled between ca. 1820 and 1853.

Betham Red Books 2nd series: Papers relating to the arms and pedigrees of various families compiled by Sir William Betham, Volume 4, ca. 1820-1850.

Letter from Sir William Betham, Ulster King of Arms, to "W. Jerden", ordering a book on Italy from "Mr. Murray" 1846 Feb. 3.

A volume of miscellaneous autograph letters including some by Sir William Betham, Lord Dunraven, Maurice Lenihan, William Torrens McCullagh, Standish O'Grady, George Petrie, William Reeves, James Henthorn Todd and John O'Donovan amongst others, with a sketch by James Gandon for a design for the Royal Exchange, Dublin [now known as City Hall], 1838-1892.

Dignities, feudal and parliamentary, and the constitutional legislature of the United Kingdom.

Volume 3 : historical and genealogical extracts from the Plea Rolls in the Birmingham Tower, Dublin Castle, Edward III, compiled by Sir William Betham, with index, [n.d., early 19th century].

Transcript, by Sir William Betham, with large additions, of Trinity College Ms. 1217 (F.4.18) Dr. Madden's 'Collection of pedigrees of Irish families and of English families settled in Ireland', 1822.

Drafts of certificates of arms and memorials for change of name, with illustrations of arms, papers in peerage cases, etc., compiled by Sir William Betham, Ulster King of Arms, 1844-1853.

Pedigrees of Gaelic families compiled by Sir William Betham, Vol. 3, [n.d., between ca. 1820 and ca. 1850].

Letters and papers of Sir William Betham, mainly concerning the Athenry Peerage, [ca. 1810-1819].

On the ring money of the Celtae /

On the affinity of the Hiberno-Celtic and Phenician languages /

Etruria-celtica: Etruscan literature and antiquities investigated :

or, The language of that ancient and illustrious people compared and identified with the Iberno-Celtic, and both shown to be Phœnician. /

The origin and history of the constitution of England :

and of the early parliaments of Ireland.