West Virginia seceded because they were pro-Union. You could say that's underrepresentation.
Part of Western Virginia left because they were Pro Union. The eastern counties of what is now WVA left because the US government threatened to shut down the prosperous rail lines going through those counties. Also, after the war, the federal government offered WVA back to Virginia. The conditions were as follows : If the state was reunited Virginia would owe the government all its pre-war debt immediately. If they allowed WVA to go on its own then the debt would be split half and half with WVA.
