OPDYCK: Genealogy, containing the Opdyck-Opdycke -Updike American Descendants of the of the Wesel & Holland families.
By C. W. Opdyke. 499p. 1889. (does not include illustrations published with some original copies)
ORTON: An account of the descendants of Thomas Orton of Windsor, CT, 1641
By E. Orton. 220p. 1896.
OSBORNE: Thomas Osborne of Ashford, Kent, England & some of his American descendants (Softcover)
By Daniel J. Weeks. 32p. Rev. ed. , 1994.
OSGOOD: Genealogy of the Descendants of John, Christopher & William Osgood who settled in New England early in the 17th century
By I. Osgood. 491p. 1894.
OSWALD: The Descendants of Henry Oswald.
Compiled By The Rev. Charles E. C. Oswald. xxix + 106p., 1907. The Descendants of Henry Oswald: to which is added an Appendix containing partial lists of the Descendants of John Everett...
OTIS: A Genealogical and Historical Memoir of the Otis family in America
By W. A. Otis. 1924. 698+28p.(w/ many photos, 944 actual pages)
OTIS: A genealogical memoir of the familyi of Richard Otis, & collaterally of the families of Baker, Varney, Waldron (& others)
By H. N. Otis. 50p. 1851.
OTIS: Some of the descendants of Ephraim Otis & Rachel (Hersey) Otis of Scituate, MA
By R. L. Weis. 74p. 1943.
OWEN: The Genealogy of Several allied families: Frazer, Owen, Bessellieu, Carter, Shaw, Wright, Landfair, Briggs, Neill, Tidwell, Johnson and others.
By Charles Owen Johnson. 543p. 1961.