Chancellorsville, Battle Of

Military engagement of the American Civil War. In May 1863 near Chancellorsville, Va., the Union army in Virginia, led by Joseph Hooker, attempted to encircle and destroy the Confederate Army of Northern Virginia, led by Robert E.

Lee. The Union army was surprised by a flanking force under the command of Stonewall Jackson. Three days of fighting ended in a Union retreat north of the Rappahannock River. The Union army lost more than 17,000 men in a force of 130,000; the Confederate army lost more than 12,000, including Jackson, in a force of 60,000.