O'BRIAN: Brian O'Brian of Berks Co., PA & Cornelius O'Bryan of Rockingham Co., VA & their desc.
By M. J. O'Brien. 18p. 1928.
O'BRIEN: Historical Memoir of the O'Briens, With notes, appendix, and a genealogical table of their several branches. Compiled from the Irish annatists
By John O'Donoghue. 551p. 1860 (Dublin).
O'BRIEN: Pennsylvania O'Briens in Land Records and in Colonial and Revolutionary Wars
By M. J. O'Brien. 15p. 1928.
O'BRIEN: The O'Briens of Machias, ME. Patriots of the American Revolution, Together with a Sketch of the Clan O'Brien
By Sherman & Murray. 87p. 1904.
O'DALY: Hist of the O'Dalys; The Story of the Ancient Irish Sept the Race of Dalach of Corca Adaimh.
comp By E. E. O'Daly. 546+30p. 1937.
O'MEAGHER: Some Historical Notices of the O'Meaghers of Iberrin
By J. C. O'Meagher. 216p. 1890.
O'ROURKE: An Irish Odyssey: History of the Family O'Rourke
By Stephen Vincent O'Rourke, 162p. 1999.
OAKS - OAKES Family Register, Nathaniel Oak of Marlboro, Massachusetts and Three Generations of his descendants
By H. L. Oak. 90p. 1906.
OBERHOLTZER: Genealogical Record of the Descendants of Marton Oberholtzer, with History and Biography
By A. J. Fretz. 254p. 1903.
OBERHOLTZER: Some Account of Jacob Oberholtzer Who Settled, About 1719, in Franconia Twp., Montgomery Co., PA & of some descendants
By Elisha S. Loomis. 412p. 1931.
OBERWINDER: Die Familie Oberwinder: Genealogical Encyclopedia of the Family Connections of Richard Maria Wilhelm Oberwinder
By Howard Metcalf. 146p. 1999.
Odell Genealogy in the US & Canada (1635-1935); Ten Generations in America. in Direct Line
By M. A. L. Pool. 123p. 1935.
ODIORNE: Genealogy of the Odiorne Family, with Notices of Other Families Connected Therewith
By J. C. Odiorne. 232p. 1875.
OGDEN - PRESTON GENEALOGY; Ancestors & descendants of Capt. Benj. Stratton Ogden & his wife Nancy (Preston) Ogden
By Stone & Powell. 31p. 1914. (Softcover)
OGDEN Family in America (Elizabethtown branch) and their English ancestor John Ogden, the Pilgrim and his descendants, 1640-1906;
By W. O. Wheeler. 532p. (656 actual pages, illustrated) 1907.
OGDEN: Family Historiy in the Line of Lt. Benjamin Ogden of NY (1735-1780) & His Wife, Rachel Westervelt
By A. Vermilve. 119p. 1906.