Graham-McCune-Morrow connections

My great-grandfather was named David Morrow Graham. He was born 3/15/1857 in Huntington Co., IN. His parents were Robert and Martha (McCune) Graham. I know very little about them except that they lived somewhere in Ohio before they moved to Indiana. Robert is believed to have been born in VA about 1897, Martha in PA about 1821. They may have lived in KY at one time.

I've often wondered about David's middle name Morrow, and whether it might be a surname connected with either the Graham or McCune family.

Does anyone know of any Graham-Morrow or McCune-Morrow connections during the late 1700's or early 1800's?