The following data is extracted from Biography and Genealogy of Western Massachusetts, 1639-1925.
ISAAC MILLS - Descended from a sterling New England ancestry, Isaac Mills was born in Southwick, Massachusetts, January 29, 1826, the son of John Mills; who was a notable figure in that region and the State, and served as United States District Attorney and State Senator. Isaac Mills attended the private schools of Mr. Lawton and Mr. Lombard, where many leading citizens received their early training. For a time he also attended Monson, Academy, but was not graduated from that institution. He entered business life as a railroad clerk in the New York, New Haven and Hartford Railroad office at Bridgeport, Connecticut. From that position he went to Scranton, Pennsylvania, remaining for a time, and later returned to Springfield, to which his father had removed when Isaac was but ten years old. In Springfield he became a junior partner in the firm of Deane, Packard & Mills, car builders.
About that time Mr. Mills married Ann L. Palmer, the oldest daughter of Edward Palmer, a prominent man of his day. Mr. Palmer was the manager of transportation from Springfield to Hartford, and captain of the steamboat "John Cooley." in 1831. In 1846 he sold out his steamboat interest to the New York, New Haven & Hartford Railroad, and bought an interest in the coal business with Mr. Ashley. Mr. Mills entered the employ of his father-in-law, and thus became connected with the business that long bore his name. This business had been started in 1833 by James Robb. In 1866 Mr. Palmer died and Mr. Mills bought the business which he conducted until his death.
While Mr. Mills kept out of politics, despite many solicitations, he always had and exhibited that interest in public affairs which a good citizen owes to his State and country. He was inclined to be liberal and independent in politics, but entered the Republican party when it was founded, and became a Mugwump. He regarded Grover Cleveland as the best type of public servant of his period, and generally Mr. Mills in recent years took his choice among candidates. He formerly attended the First Church up to 1874, when he became an attendant of the South Church, Springfield. He died February 18, 1892, at his home on Crescent Hill, Springfield.
The passing of this fine man was a sore grief to all who knew him well, and throughout the city the sense of loss was felt and expressed. The figure of Isaac Mills conveyed the impression of a sturdy, reliable and kindly manhood, and it was familiar to all Springfield. His local associations ran back to his boyhood, and the roots of his acquaintance struck deep into Springfield life. He was a modest man who had a shrewd hold upon a sound philosophy that gave him a grasp on certain satisfying things in life. Within the round of his business labors and the circle of his exceptionally happy home life he was content to remain. No attempt to draw him into public office could avail, and the appeal came to be abandoned as hopeless. Mr. Mills and the late Governor Trask were intimate friends. Mr. Mills was honest and reliable, and had no enemies. He liked a good horse and loved to speed him. He was a kind and devoted husband and father. He is survived by two daughters, Emily and Elizabeth Howard Mills. A son died in infancy. Mrs. Roswell G. Shurtleff was the only sister of Mr. Mills, and there were two brothers, Enos Mills, of Springfield, and John Mills, a contractor, of Chicago, all now deceased.
Source: Biography and Genealogy of Western Massachusetts, 1639-1925