The War In 1861
In response to popular cries of On to Richmond, a Union army under Brigadier General Irvin McDowell began on July 16 a slow advance from near Washington toward the Confederate capital. On July 21, the Union forces encountered Confederate troops under Generals Joseph E. Johnston and P. G. T. Beauregard about 30 miles (48 km) southwest of Washington. In the ensuing Battle of Bull Run (or Manassas), the Northern troops were defeated and forced to retreat to the Potomac River.
In early summer, Union troops led by Major General George B. McClellan drove Confederate forces out of the western part of Virginia. This part of the state, where there was little sympathy for the Confederacy, formed a pro-Union government, and in 1863 was admitted to the Union as the state of West Virginia. In late July, Lincoln summoned McClellan to command the main Union force in the East, the Army of the Potomac. McClellan spent the rest of the year organizing and training his army.