William S. Rosecrans was born Sept.6, 1819 at Delaware City, Ohio, the son of Crandell Rosecrans and Jane Hopkins and the great-grandson of Stephen Hopkins, colonial Governor of Rhode Island and a signer of the Declaration of Independence. Hopkins also co-authored with John Adams, the draft of the Articles of Confederation.

Rosecrans was a graduate of the Class of 1842 at West Point ( 5th in the class of 56). Among his classmates were: James Longstreet, Richard H. Anderson, Abner Doubleday, John Newton, George Sykes, Seth Williams, Lafayette McClaws, Alexander P. Stewart, John Pope, D.H. Hill, and Earl Van Dorn. He was the roommate of James Longstreet and A.P. Stewart.

Rosecrans was assigned engineering duty upon graduation but resigned from the Army in 1854, and became an architect and a civil engineer. His rise in business was astounding. He took over direction of mining in western Virginia (West Virginia today) where his geological surveys pointed with remarkable accuracy to profitable new veins of coal. He became President of a navigation company formed to transport coal. He was also an inventor. Numbered among his inventions were odorless oil, a round lamp wick, a short practical lamp chimney, and a new and economical method of manufacturing soap. While in the laboratory a safety lamp exploded and burned him terribly. He was bedridden for 18 months recovering from the burns. Just as his recovery from burns were coming to a conclusion the Civil War broke out.

His first duties in the war were for the state of Ohio when he became the drillmaster for the 'Marion Rifles'. After which he became the engineering officer that laid the plan for Camp Dennison, Ohio and eventually became the Commanding Officer of the 23rd Ohio Volunteer Infantry, which among its members were Rutherford B. Hayes, William McKinley, and Stanley Matthews, a future Associate Justice of the Supreme Court.

Rosecrans was soon appointed a Brigadier General in the regular Army in which he was a successful commander at Rich Mountain, Virginia. After Rich Mountain, George McClellan received much credit for the success there and was promoted to the Commanding General of the Army of the Potomac and eventually General-in-Chief of the Union Armies. Yet it was Rosecrans that developed and carried out the plans that gained the victory at Rich Mountain. McClellan did not give him any credit in the official reports. Thus Rosecrans refused to go east with McClellan and requested a transfer to the west.

In the west, Rosecrans was placed in charge of the left wing of the Army of the Mississippi at Iuka and Corinth. At both he did ably. After Corinth animosities between Grant and Rosecrans arose. Grant blamed Rosecrans for not pursuing the Confederate Army after Corinth and Rosecrans placed blame on Grant for not sending reinforcements during and immediately after the Battle of Corinth.

After Corinth, Rosecrans was given command of the XIV Corps and promotion to Major General. The promotion was back dated to March 1862 so that Rosecrans would outrank Major General Thomas. As Commanding General of the XIV Corps Rosecrans secured a victory at Stones River(Murfreesboro) and immediately began the reorganization of the XIV Corps into the Army of the Cumberland. He then embarked upon the Tullahoma Campaign and ousted the Confederates from Chattanooga with fewer then 500 casualties in the whole army.

Rosecrans was loved by the men of his Army but was harsh on his officers. A very problematic fault of Rosecrans was that once a battle began he became very excitable which led him to stutter and become very difficult to understand. Another problem of Rosecrans was he would micro-manage the movements of units himself instead of using the chain of command to direct movements. These problems were never more apparent than at Chickamauga. Rosecrans issued an order to General Wood "to close in and support his left." This order created a hole in the Union line which coincided with Longstreet's attack and led to the Confederate victory. Because of the defeat, Rosecrans was relieved of command of the Army of the Cumberland and would eventually be given command of the Department of Missouri until wars end.

Rosecrans resigned from the Army in 1867 to resume his career in business. He eventually would become Minister to Mexico, serve in Congress representing California, and register of the Treasury. William S. Rosecrans died March 11, 1898 at Redondo, California and is buried at Arlington National Cemetery.