Children of William Alexander:
Hugh Alexander(b.1767)

Hugh is also mentioned in his father's will.

Here is the info on his father's memorial:

Jacob Alexander's first born son was
William Alexander (1734, Down, Ireland - d. btw Nov 1818 - 10 Feb 1819 Great Cove Ayr, Beford, PA)
William was married three times, First wife Unknown and
third/last wife's name was Susannah.
William's second marriage on 14 Nov 1770 to Isabel Alexander (1735-1780,possible cousin of Wm), produced many children, one of which is (id 78211810): Jacob Alexander(1779-1851) (the grandson of this Jacob Alexander)

Some of his siblings included(mentioned in his father's will) - children of William Alexander and Isabel Alexander from above:
Andrew Alexander(b.1786)
William Knox Alexander(1782-1829)
Cairns/Carnes Alexander(1778-1838),
Isabel Alexander(b.1780),
Sarah Ann Alexander(1784-1867),
Susannah Alexander (1784-1831),
John Allen Alexander(1788-1870)
1/2 siblings
Hugh Alexander(b.1767) &
Mary Alexander(1769-1843).

Not sure where Knox Alexander fits. He is mentioned in his father's will (William) twice, as the executor and then what land he can own.

Also listed is Jacob Alexander as a son.

Here is the typed will of William Alexander:

Will of William Alexander

In the name of God amen (?), this 8th day of November 1818. I William Alexander of the county of Bedford [Pennsylvania], and his township, who being weak of body but perfect mind and memory wherefore calling to mind the shortness and uncertainty of my time, knowing that it is appointed for all men once (?) to die and after death to judgement, do make and ordain this my last will and testimony and first of all I recommend my soul to God, that gave it and anybody, I recommend to the earth (?) to be buried in a decent and Christian-like manner at the direction (?) of my executions and tutelage (?) to look (?) wordly estate as ?? God to bless me ?? in this life I give and disclose (?) in this (?) the following manner.

I first allow all my debts and funeral expenses to be paid. Next I leave to my dearly beloved wife the plantation I now live and during her widowhood and to help the children with her sublet (?) ?? as formerly.

I allow my son William Knox to have free the north side of the place, where he now lives on as far as pearcels (?) live to a hickory comes, then a share live as far as a marked black oak, then across the hollow to the partition fence and ? that a ? live til the upper (?) what ever is on the north side of that live.

I allow him for his past services.

Next, Jacob and Knox, Hugh, Mary and Andrew they (?) have got some part already and have the rest of the children I allow to have as much and all myland except the place I live and allow my executors to sell and Conway (?) and the money arising from said lands to be equally divided among all my children. What share I have in Alic(?) burn pike I allow my wife to pay and have the benefit of it during her life time. At her death the five shares to be sold (or sealed?) the plantation and what other property I leave her, she is to have as long as she continues my wife.

If she marries, the place to be sold and estates (?) other (?) anticts (?) except such (?) as shall be mentioned have afterwards and be divided among my children equally. If she marries she gets abiding of cloas (?)and bed a whish(?) and chest of drawers her saddle bridle her choice of one of the horses and two cows and fore shel(?) the plantation to be sold by my executors and fifteen hundred dollars left in the ?? hands at intervals and to be paid to my wife quarterly or if the fourteen(?) docs(?) not kept it is to be let out to a sure hand on the fore said terms and paid to my widow but if she continues my wife(?) the with the concurrent (?) of my executors, she enjoys all my movable property she doing(?) as before mentioned, but if other ways the money she draws the interest of it to be equally divided among my heirs.

I allow Joseph Rinnion (?) to remain with my wife til he comes of age if she continues my widow of my debts cannot be paid otherwise it must be paid out of the money arising form the sale f the land if any of my children offers to sell off then share of the land it must be with the consent of a majority of the ?? and likewise appoints Francis Kendall and ?? Knox Alexander my executors in ?? where of them(?) set (?) my hand and sail the day and year above mentioned. William Alexander

Witness?? John Alexander Michael Schman(?)

Here is the rest of the information found on the memorial page of his father Jacob Alexander:

Jacob was the father of many, (uncertain of number) including the following:

Susannah "Susan" Alexander (1749-1825) who married on 8 Jul 1772 in Mercersburg, PA, John Shannon Alexander (1743-1825)

This memorial is for her. I'm not sure if she was buried in Pennsylvania or not. It's an assumption based on the memorial info below.

Here is the memorial information found on the page of her father Jacob Alexander:

Jacob Alexander(1709-1792 *His will was signed 19 Jul 1778 and proven on 14 Nov 1792) who was a Scottish Immigrant born in County Down, Ireland and immigrated to the United States to escape bitter British persecution for practicing their deeply felt Presbyterian principles.

This family settled in/early founders of Great Cove Ayr, Fulton County, Pennsylvania (Amazing historic stories/books, settlement, War, Indian Battles) & Early Alexander land patents.

This Jacob was the father of many, (uncertain of number) including the following:
dau Martha Alexander (b.abt 1737),
Polly Alexander (b.abt 1740, d.Aft 1791),
Margaret Alexander (b. Abt.1742 d.Aft 1791),
Hugh Alexander (b. Abt 1747, he participated in the Revolutionary War and many fights with the Indians, much written about him),
Isabel Alexander (b. Abt 1750),
Susannah "Susan" Alexander (1749-1825) who married on 8 Jul 1772 in Mercersburg, PA, John Shannon Alexander (1743-1825)

Lastly, Jacob's first born son was
William Alexander (1734, Down, Ireland - d. btw Nov 1818 - 10 Feb 1819 Great Cove Ayr, Beford, PA)
William was married three times, First wife Unknown and
third/last wife's name was Susannah.
William's second marriage on 14 Nov 1770 to Isabel Alexander (1735-1780,possible cousin of Wm), produced many children, one of which is (id 78211810): Jacob Alexander(1779-1851) (the grandson of this Jacob Alexander)

Some of his siblings included(mentioned in his father's will) - children of William Alexander and Isabel Alexander from above:
Andrew Alexander(b.1786)
William Knox Alexander(1782-1829)
Cairns/Carnes Alexander(1778-1838),
Isabel Alexander(b.1780),
Sarah Ann Alexander(1784-1867),
Susannah Alexander (1784-1831),
John Allen Alexander(1788-1870)
1/2 siblings
Hugh Alexander(b.1767) &
Mary Alexander(1769-1843).

In 1809 Jacob married Susannah Morrison(1791-1861).
They were parents to:
Isabella Alexander(1809-1895),
Esther Alexander (1812-1869),
William Alexander (1812-1875),
Ann Alexander (1813-1893),
David Alexander (1816-1863) &
George Washington Alexander(1819-1902).

In my search for this family's ancestry/history, I have come across some very informative sources/history/info. One of which is a land patent to Jacob signed by President John Quincy Adams. I Googled Jacob Alexander and found there is a book entitled; 'Ohio Genealogical Quarterly' in it is a story/bio entitled, Jacob Alexander And some of his Decendants (pg 461), By William H. Hannah. Also very informative on this family is, THE HISTORY OF FULTON COUNTY PENNSYLVANIA, www.pa-roots.com/beford/history/historyoffultoncounty.

The above information was taken from the memorial of Jacob Alexander (memorial id: 78211810) , the grandson of this Jacob Alexander

I have put burial unknown at this point. I put that death was in Fulton County, Pennsylvania because of the information above.