Hi, What research have you already done.
re your research of your Ggrandfather George MOORE - born 1848 born [where] Moved to Clinton PA U.S.A.
Married Sarah EDGAR.
Perhaps the Registration of Marriage/ Long form Marriage Certificate:
for George MOORE to Sarah EDGAR - will show the place of birth - names of parents including maiden name of the mother. All depends on the requirement at the time.
George MOORE may have made application for U.S. Citizenship
That should show some personal information - may show names of his parents etc
Border Crossing Records: - If your GGrandfather was Cree it is possible that he had free access to crossing the border
If Not, Don't know if they were required at the time.so search Border Crossing records