Custer was born on December 5, 1839 in New Rumley, Ohio, to Emanuel Henry Custer (1806–1892), a farmer and blacksmith, and Marie Ward Kirkpatrick (1807–1882).

According to late 20th century research, Custer's ancestors, Paulus and Gertrude Küster, who followed the first thirteen immigrant German families from Krefeld and surroundings, had emigrated to North America around 1693 from the Rhineland in Germany.

George Armstrong Custer's Family Tree