William S. Rosecrans was born on September 6, 1819
at Kingston, Ross County, Ohio, the son of Crandell and Jane
(Hopkins) Rosecrans and the great-grandson of Stephen Hopkins,
a signer of the Declaration of Independence and colonial governor
of Rhode Island. Stephen Hopkins also co-authored the draft of
the Articles of Confederation.
William Rosecrans completed preparatory studies and was appointed to the United States Military Academy at West Point in 1838. In 1842 he graduated from West Point 5th in his class of 56 and on assigned engineering duty upon graduation. William was brevetted to second lieutenant, United States Corps of Engineers, July 1, 1842 and promoted to second lieutenant on April 3, 1843. He served as assistant professor of engineering at the Military Academy from 1843 to 1847 and was thereafter placed in charge of various Government surveys and improvements from 1843 to 1853.
On April 1, 1854 he resigned from the Army in 1854 and became an architect and civil engineer. In 1856 he became president of the Coal River Navigation Company, Kanawha County, Virginia (now West Virginia) and organized the Preston Coal Oil Company in 1857 where he engaged in the manufacture of kerosene.
When the Civil War broke out, Rosecrans reentered the service on June 7, 1861, as colonel of the Twenty-third Regiment, Ohio Volunteer Infantry. 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 Twenty-third Regiment, 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 appointed a Brigadier General in the regular Army on May 16, 1861, in which he was a successful commander at Rich Mountain, Virginia, for which 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 requested a transfer to the west. In the west, Rosecrans was placed in charge of the left wing of the Army of the Mississippi.
Rosecrans was given command of the XIV Corps and a promotion to Major General. The promotion was back dated to March 1862. As Commanding General of the XIV Corps, Rosecrans secured a victory at Stones River 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 relieved of command of the Army of the Cumberland and given command of the Department of Missouri until wars end. Rosecrans resigned from the Army on March 28, 1867 to resume his career in business and moved to California and settled in Los Angeles.
In 1868, President Andrew Johnson appointed him United States Minister to Mexico, a post which Rosecrans served in Mexico for two years, before becoming involved in mining interests there. He returned to California in 1869 where he continued to be involved in mining. He again engaged in civil engineering becoming president of the Safety Powder Company in Los Angeles, in 1875. He was elected as a Democrat to the Forty-seventh and Forty-eighth Congresses (March 4, 1881-March 3, 1885) where he served as chairman, Committee on Military Affairs (Forty-eighth Congress). He was not a candidate for renomination in 1884. He returned to California and served as a regent of the State university in 1884 and 1885 before President Grover Cleveland appointed him Registrar of the Treasury in 1885, a post he held until 1893. Reappointed brigadier general on the retired list, United States Army (act of Congress, February 27, 1889), and officially retired on March 1, 1889.
He returned to him home in Redondo, Los Angeles County, California, where he died on March 11, 1898. William S. Rosecrans was interned in the Rosedale Cemetery and reintered in the Arlington National Cemetery on May 17, 1902. He is buried in Section 3 (1862) of Arlington National Cemetery.