What led to union troops kicked out of Virginia?

Union troops were expelled from Virginia primarily due to strategic military defeats and the effective tactics employed by Confederate forces. Key battles, such as the First Battle of Bull Run in 1861, showcased the Confederates' ability to leverage their knowledge of the terrain and mobilize quickly. Additionally, the Confederacy's strong leadership and the motivation of its soldiers contributed to their success in repelling Union advances, ultimately leading to the withdrawal of Union forces from the state.