Harmon married Matilda Miller between 1859-1860. In the 1860 census, Harmon (25) and Matilda (20) are living in Alleghany Township, Somerset County, and were married within the past year.
In the 1880 census, Harmon (44) and Matilda (40) are living in Congress Township, Wayne County, Ohio with 6 children Wm (19, b.PA); Anne H (16, b.PA); Lydia C (14, b.PA); Dora E (10, b.OH); Joseph E (8, b.OH); Robert M (6, b.OH); and Alda E (1, b.OH). So it appears they moved from PA to Ohio between their 3rd and 4th child (10-14 years prior to 1880).
In the 1900 census, Hermon (65) and Matilda (59) are in Fairhope Township, Somerset County PA. Son Robert (25) is with them and one grandson, Harry G. GRAY (age 16). The 1900 census gives Harmon's birthdate as December 1834 and Matilda's as March 1841. Matilda had 9 children with 7 living in 1900.
My Brick Wall is finding Harmon's parents, and also an exact date of death. I believe he was buried at a potter's field in Somerset. I am told this was at the old Somerset State Hospital, where the prison is now.