George Brinton Mcclellan, an American soldier and engineer, born in Philadelphia, Dec. 3,1826. He studied at the university of Pennsylvania, and in 1842 entered the military academy at West Point, where he graduated second in his class in 1846, and was assigned to duty as brevet second lieutenant in the corps of engineers. He served with distinction during the Mexican war, and was successively brevet-ted as first lieutenant and captain. In 1851-'2 he was assistant engineer in the construction of Fort Delaware; in 1852-'3 chief engineer in the department of Texas, having in charge the surveys of the coasts of that state; in 1853-'4 engineer for the exploration and survey of the western division of the proposed Pacific railroad; and in 1854-'5 he was on special service in collecting railroad statistics for the war department. In 1855-'6, having been made captain of artillery, he was a member of the military commission to visit the seat of war in the Crimea. He resigned his commission June 16,1857, to take the post of chief engineer of the Illinois Central railroad, of which he was chosen vice president in 1858; and in 1860 he became president of the St. Louis and Cincinnati railroad.

At the opening of the civil war he was commissioned as major general of Ohio volunteers, and was placed in command of the department of the Ohio, comprising the states of Ohio, Indiana, Illinois, and the western portions of Pennsylvania and Virginia. He was made major general in the regular army May 14, 1861, and commanded in several engagements in western Virginia, which resulted in clearing that region of the confederate forces, for which he received on July 15 the thanks of congress. On July 22, the day after the federal defeat at Bull Run, he was summoned to Washington, and was placed in command of the division of the Potomac, and shortly after of the army of the Potomac. Upon the retirement of Gen. Scott (Nov. 1) he was appointed general-in-chief of the armies of the United States. He took the field in March, 1862, and having in the mean time been relieved of the command of all the forces except the army of the Potomac, he set out for the peninsula of Virginia, and laid siege to Yorktown, which was abandoned by the confederates as soon as his batteries were ready to open fire.

The retreating confederates, under Gen. J. E. Johnston, made a stand at Williamsburg (May 5) long enough to enable their trains to get off, and fell back toward Richmond. McClellan, moving slowly, reached the Chickahominy about May 20, and opened the campaign against Richmond, which was brought to a virtual close by the battle of Malvern Hill (July 1), after which he fell back to Harrison's landing, where he intrenched himself. (See Chickahominy.) Gen. Halleck, having in the mean while been made general-in-chief, ordered McClellan (Aug. 24) to return with his whole army to Fortress Monroe and Yorktown. Gen. Lee, almost simultaneously, moved from Richmond to threaten Gen. Pope, who had been placed in command of the Union forces in northern Virginia. The result was the defeat of Pope at Bull Run, Aug. 29, 30. Pope, at his own request, was relieved from the command of the forces at and about Washington, which was conferred upon McClellan. The confederates then undertook the invasion of Maryland, which was brought to a close by the battle of Antietam, Sept. 16, 17. (See An-tietam.) They then crossed the Potomac and fell leisurely back toward the Rapidan. Great dissatisfaction was felt at the slowness with which McClellan followed them, and on Nov. 7, when he appeared to be making preparations for an attack in force, he was superseded in command by Gen. Burnside. McClellan was directed to proceed to Trenton, N. J., there to await further orders, and took no further part in the war.

The democratic national convention, held at Chicago, Aug. 31,1864, nominated him for the presidency. He received only the 21 electoral votes of the states of Delaware, Kentucky, and New Jersey, the remaining 212 electoral votes admitted being cast for Abraham Lincoln. Of the popular vote 2,223,035 (a little more than 55 per cent.) were cast for Lincoln, and 1,811,754 (a little less than 45 per cent.) for McClellan. The latter resigned his commission in the army on the day of the election, Nov. 8, 1864, took up his residence in New York, and afterward went to Europe. In 1868 he returned from Europe and took up his residence near Orange, N. J., and engaged in practice as an engineer. By the will of Mr. Edwin A. Stevens he was placed in charge of the Stevens floating battery which had for a number of years been in course of construction at Hoboken. He was also made superintendent of the construction of the railway bridge over the Hudson river, near Pough-keepsie, N. Y., and superintendent of docks and piers in the city of New York, but resigned the latter office in 1872. He has translated from the French " A Manual of Bayonet Exercises," adapted for the use of the United States army (1852), and written a volume of the government reports of the "Pacific Railroad Surveys" (1854), a volume of the reports of the European commission, "The Armies of Europe," etc, printed by order of congress (1861), and "Report on the Organization and Campaigns of the Army of the Potomac " (1864).