This source lists Brian (son of Phelim) O'Neill as having three sons namely
Cites the 1739 Will of John, Edenduffcarrick, Esquire, County Antrim. This is probably Hugh's brother who died in 1739, he was known as French John. Additionally, there is French John's sons will which was written in 1768 naming, Charles, Shane's Castle, county Antrim, Esquire. This is a large will.
Page 361 of this authoritative work talks about: The paternal great-grandfather of Judge John Belton O'Neall "belonging to the ancient house of O'Neall of Shane's Castle, Antrim, Ireland." He is writing of his great-grandfather Hugh O'Neill/O'Neall.
Published on microfilm and available from any Family History Center this substantial work of Mrs. Dick's, who died in 1995, is compelling and essential for the study of the O'Neall surname in America. Included also are various spellings such as O'Neal and Neal and includes generation descendant charts for many of the direct descendants of emigrant Hugh O'Neall. The history of O'Neill in Ireland is discussed, includes bibliography.
A Glance Back Over Our Shoulders; Pride in our Past-Faith in our Future From 1720-1984, Elizabeth Andrews Duncan and Karen EK Schultz, Includes the history of the O'Neall family since emigration to America.
Proof of the Pedigree of O'Neill, Library of the Royal Society of Antiquaries.
Story of the Irish Race, Seumas MacManus, Devin-Adair Co., Old Greenwich, Connecticut, 1893
Scotch Highlanders in America, J P McLean, An account of an O'Neill's departure on May 9, 1729 for America.
The O'Neill's of Spain, Micheline Walsh, Belgrove University, Dublin, 1957.
Desmond O'Neill, A Genealogical Composition of the Ancient and Royal Family of O'Neill, 538p, 1995, Desmond O'Neill, Ireland, includes Hugh as son of Bryan O'Neill
Burke's Landed Gentry of Great Britian and Ireland, 1868, p. 1121, from Trinity College, Dublin, Ireland.
First Families of America, Page 189
Ulster Historical Foundation The O'Neills of Ulster; High Kings of Ireland by Sir Iain Moncreiffe of that Ilk, with additional information by Kathleen Neill, AUGRA (Hon-Life Mem.) & IGOC (RG), Page 64 notes have been added by present day genealogists according to the Royal O'Neill Clan Society, from whom this book originated.
Trinity College Genealogy Chart