From the book, "The McKinley Family" by H.T.O. Blue (Genealogist) pg 8:
"Strange as it may seem James was married into a family of workers in iron. The family was named Rose. They were among those who had fled from England to Holland for refuge from religious persecution, at about the time the McKinley's were struggling for freedom of belief in Scotland, Andrew Rose was among the leaders of the English Puritans. He came to America from Holland with William Penn, and received a grant of land encompassing nearly sixty miles where Doylestown, Pennsylvania, now stands.
Mr. Rose was a prominent factor in the early colonial history of Pennsylvania. He prospered in business and became a member of th legislative council of the colony. His son, Andrew Rose, Jr., was a soldier in the Revolutionary War for a short time but after the Battle of Monmouth it was decided that he could be of more service to his country in his iron foundry than as a bearer of a musket in the field. He manufactured cannon and other ordance supplies during the remaining years of the war.
After the war Andrew Rose, Jr., removed from Bucks County, Pennsylvania, to Center County and continued his business as an iron founder. It was about this time that the Rose and McKinley families formed an acquaintanceship which resulted in several marriages between the different members of the two families."