George Duffield, was, on July 6, 1776, appointed by Governor Morton, Chaplain to the Pennsylvania forces in the Revolutionary Army.

On the Sunday following he dismissed his congregation with these words: "I hope the women will worship here in silence on the next Sabbath, and the men will be with me in Washington's Army."

In the campaign from Nashville to Chattanooga, 1863, he was attached to the headquarters of General George H. Thomas, and given command of the mounted Provost Guard of the Eleventh Army Corps, the members of which he was allowed to select, and took an active part in all the important battles of that campaign, including Stone River and Chickamauga, where he was wounded.

During the Siege of Chattanooga, October 23, 1863, by the Confederate forces under General Braxton Bragg, he was promoted Post Adjutant.

During the campaign of Thomas from Chattanooga to Atlanta, Duffield was acting Provost Marshal General of the Army of the Cumberland, participating in all the hard fought battles of this Union commander, among them being Resaca, Missionary Ridge, Peach Tree Creek and Jonesboro.

While in this position he carried to a successful termination suits brought to recover from the County Treasurer, moneys received from fines in the municipal courts.

Under provision of the Michigan State Constitution these funds were required to be applied to the support of a public library, but had been diverted to the payment of expenses of the courts and to other uses.

[attribution needed][1][2] Duffield was on the staffs successively of Governors Bagley, Croswell, Jerome and Alger, and kept up a lively interest in the Detroit Light Guard with which he had long been connected.

On June 14, he assumed command of a separate Brigade of the Second Army Corps, composed of the Thirty-third and Thirty-fourth Michigan and Ninth Massachusetts Volunteers.

It was the desire of the Government to reinforce General Shafter's army which had just landed in Cuba, but only one vessel, the transport Yale, was then available, and that could carry only one brigade.

Duffield's brigade was then on a practice march to the Potomac, but it returned to camp, won in the test and was dispatched to Santiago.

In the Battle of July 1, Duffield was assigned to the duty of making a demonstration on the extreme left, at Aguadores, without any means of crossing the stream, and thus coming into the general engagement.