They were Delaware, Maryland, Kentucky, and Missouri, and after 1863, the new state of West Virginia. To their north they bordered free states of the Union and to their south (except Delaware) they bordered Confederate slave states.
The border slave states of Maryland, Delaware, Kentucky, and Missouri remained with the Union, although they all contributed volunteers to the Confederacy. Fifty counties of western Virginia were loyal to the Union government, and in 1863 this area was constituted the separate state of West Virginia. Secession in practical terms meant that about a third of the population with substantial material resources had withdrawn from what had constituted a single nation and established a separate government.
