William Starke Rosecrans, an American soldier, born at Kingston, Ohio, Sept. 6, 1819. He graduated at West Point, and served for a year as assistant engineer in the construction of fortifications at Hampton Roads, Va. From 1844 to 1847 he was assistant professor of engineering and natural philosophy at West Point. He resigned his commission in 1854, and became a civil engineer and architect at Cincinnati, was superintendent of a coal company, and also engaged in the manufacture of kerosene oil. At the commencement of the civil war he became voluntary aide-de-camp to Gen. McClellan, who commanded the department of the Ohio, and was soon made brigadier general of the regular army. He took a prominent part in the operations in Western Virginia, and was put in command of that department when McClellan was placed at the head of the army. In March, 1862, he was made major general of volunteers, and was placed in command of the army of the Mississippi, and fought the battles of Iuka (Sept. 19) and Corinth (Oct. 3, 4), in both of which he was victorious.

In October he was made commander of the army of the Cumberland, and fought against Gen. Bragg the battle of Murfrees-borough or Stone river, Dec. 26, 1862, to Jan. 2, 1863. Crossing the Cumberland mountains and the Tennessee river, he was defeated by Bragg at the battle of Chickamauga, Sept. 19, 20, and was relieved from the command and succeeded by Gen. Thomas. In January, 1864, he was placed in command of the department of the Missouri. He was mustered out of the volunteer service in 1866, and resigned his commission in the United States army in 1867. In 1868-'9 he was for a few months minister to Mexico.