William and Hannah had 10 children who mostly stayed in Loudoun County. His oldest daughter, Elizabeth, married the Quaker, Joseph Worthington in Loudoun County and later moved with him to Knox County, Ohio. Their other children were, Joshua, Craven, Ann, Landon, Herod, Sally, Turner, Hector and Norval.

William's parents were John and Sarah (Morris) Osburn.

Here is William's 1805 Will to help document his family:

I William Osborn of the County of Loudoun and Commonwealth of Virginia do make ordain and establish this my last Will and Testament in manner and form following that is to say I give and bequeath to my wife Hannah Osborn all my estate real and personal in trust during her natural life with power and Authority to sell and dispose of any part of the same that she may think necessary for the payment of my debts. And it is my Will and desire that at the decease of my said Wife all my estate both real and personal shall bd sold and the money arising from such Sale be equally divided among all my children Share and Share alike except daughter Elizabeth Worthington my daughter Ann Sepley and my son Joshua Osborn they having received each of them about five hundred and twenty Dollars from me by way of Advancement it is my Will that they receive no more than what will make them equal with the rest of my children including that sum. And lastly I do constitute and appoint my Wife Hannah Osborn Executrix and my sons Joshua Osborn & Craven Osborn Executors of this my last Will and Testament hereby revoking all other and former Wills by me heretofore made and establishing this as my last Will & Testament In Witness whereof I have hereunto set my hand and Affixed my Seal this Seventeenth day of October One thousand eight hundred and five.

Unfortunately, in the above Will, William names his wife Hannah and only two daughters and two sons. However, his son Joshua seems to name all of his siblings and many nieces and nephews in his 1847 Will which is abstracted below.

I Joshua Osburn of the County of Loudoun and state of Virginia do hereby make my last will and testament in manner and form following
that is to say, I desire that my Estate real and presonal lying and being in the state of Virginia and my house and lot lying and being in Frederick Town Knox County Ohio be sold at public or private sale at the discretion of my Executors herein after named, but not sold to give possession until the expiration of any lease that I may have given on my land should i die before the expiration of such lease and the monies arising from such sale to be applied and disposed of as follows: brother Hector, brother Norval, brother Herod, brother Landon, (brother) Craven, sister Elizabeth Worthington and Amanda (Lesley) Fox [daughter of Joshua's sister, Sarah Leslie.

In addition, William's son Landon Osburn names all of his brothers and two of his sisters in his 1815 will, abstracted as follows: my sister Elizabeth Worthington, my brother in Law Thomas Lesslie, my brothers Joshua Osburne, Cravan Osburne, Turner Osburne, Herod Osburne, Heaton [Hector] Osburne & Norval Osburne.

In addition, the gravestones of William's children mostly name their parents as William and Hannah.