There is much opposition to Virginia's secession vote from the western counties of the state, which are economically tied closer to western Pennsylvania and Ohio than to eastern Virginia.

Following the secession vote in Richmond in April, John Carlile, a Unionist leader from northwest Virginia, leads a meeting at Clarksburg that calls for a convention to meet at Wheeling the next month for determining what steps "the people of Northwest Virginia should take in the present emergency."

The 1st West Virginia Volunteer Infantry Regiment is also raised the same month as Union infantry, participating in the first battle of the campaign at Philippi.

To organize Union forces in the area, George B. McClellan is appointed commander of the Department of the Ohio, covering Ohio, Indiana, Illinois, western Pennsylvania, and western Virginia.

He gathers several regiments raised in Ohio, Indiana, and western Virginia and moves into Virginia in early May, moving along the Baltimore and Ohio Railroad and the Kanawha River.

West Virginia, both before and after it is granted statehood, will raise several infantry, cavalry and artillery regiments throughout the war to fight on the side of the Union.

The Confederates appoint several commanders to organize troops in western Virginia: Colonel George A. Porterfield in northwestern Virginia, and Brigadier Generals John B. Floyd and Henry A. Wise in the Kanawha Valley.

This divided command structure prevents the Confederates from coordinating their response to the Union invasion; in addition, General Robert E. Lee, commander of the Virginia militia forces, will underestimates the strength of Unionist support in western Virginia.