I gave up yrs ago, but thought I'd give it another shot.
William BOYD b 1800/01 Co Tyrone; emi US 1823; m Margaret MC FARLAND, Belmont Co Ohio, b 1802 d/o Andrew/Agnes "Nancy" nee MC FADDEN...also of Co Tyrone [emi c 1812]. Wm was a weaver in IRE, and a couple of yrs in Pennsylvania before moving to OH.
Wm's Belmont Co OH bio states parents are James BOYD/Margaret EMOCK [not sure if correct spelling]. Wm's alleged older sister Isabel was b c 1790, m James MC NIECE; bro Rev Samuel BOYD b c 1814 [emi 1843]. Sam's theology school info states b Strabane, but I've also heard West Longfield Parish mentioned for my BOYD family. There are probably many siblings in-between these 3.
I've searched for yrs to find info on James & Margaret, but BOYD is so common. If they are, in fact, the parents of Isabel, I'm guessing their bdates 1765-70. I believe there are several MC KELVEYs within this family.