Border states (Civil War) in the context of "West Virginia in the American Civil War"

During the American Civil War, Missouri was a hotly contested southern border state populated by both Union and Confederate sympathizers. It sent armies, generals, and supplies to both sides, maintained dual governments, and endured a bloody neighbor-against-neighbor intrastate war within the larger national war.

A slave state since statehood in 1821, Missouri's geographic position in the central region of the country and at the rural edge of the American frontier ensured that it remained a divisive battleground for competing Northern and Southern ideologies in the years preceding the war. When the war began in 1861, it became clear that control of the Mississippi River and the burgeoning economic hub of St. Louis would make Missouri a strategic territory in the Trans-Mississippi Theater.

During the American Civil War (1861–1865), Maryland, a slave state, was one of the border states, straddling the South and North. Despite some popular support for the cause of the Confederate States of America, Maryland did not secede during the Civil War. Governor Thomas H. Hicks, despite his early sympathies for the South, helped prevent the state from seceding.

Because the state bordered the District of Columbia and the opposing factions within the state strongly desired to sway public opinion towards their respective causes, Maryland played an important role in the war. The Presidency of Abraham Lincoln (1861–1865) suspended the constitutional right of habeas corpus from Washington to Philadelphia. Lincoln ignored the ruling of Chief Justice Roger B. Taney in "Ex parte Merryman" decision in 1861 concerning freeing John Merryman, a prominent Southern sympathizer arrested by the military.

The history of West Virginia stems from the 1861 Wheeling Convention, which was an assembly of northwestern Southern Unionist from northwestern counties of the state of Virginia. They formed the Restored Government of Virginia, which purported to represent the government of the entire state of Virginia but in fact only represented those areas controlled by the Union army. It was recognized as the official government of the state of Virginia by Congress, and it repealed the Ordinance of Secession that Virginia made at the start of the American Civil War (1861–1865). It created West Virginia from the western counties under Union Army control. The new state was formed and recognized by the U.S. Congress on June 20, 1863, and protected by the U.S. Army.

The area that comprises West Virginia was originally part of the British Virginia Colony (1607–1776) and the western part of the U.S. Commonwealth of Virginia (1776–1788), and state of Virginia (1788–1863). Western Virginia became sharply divided over the issue of secession from the Union, leading to the separation from Virginia, and formalized by West Virginia's admittance to the Union as a new state in 1863. West Virginia was one of five Civil War border states.