Born May 11, 1866 in Rock Island, Illinois, Wallace was the first child and son of Henry Wallace and Nancy "Nannie" (née Cantwell) Wallace. John Wallace, father of the elder Henry, was an Ulster Scots immigrant from the village Kilrea in County Londonderry, Ireland who arrived in Philadelphia in 1823 and later owned a farm in western Pennsylvania, which the elder Henry worked on as a child with his seven siblings. The elder Henry moved west at 18 and became a Presbyterian minister. He married Nancy Cantwell, the daughter of an Ohio politician, in 1863.