The term “border states” dates back to the American Civil War of 1861 to 1865. This term was used to describe slave states that did not secede from the Union or joint he Confederacy. The term “border state” was used because free states bordered the states to the north. Four of the five border states also shared borders with Confederate states to the south.
In Delaware, slavery was rare leading up to the Civil War. Both houses of the General Assembly rejected secession from the Union.
In parts of Maryland, there was support for the Confederacy. However, Washington D.C. would have been surrounded if Maryland had joined the Confederacy. During the Civil War, Maryland’s state legislature wanted to stay neutral. During the war, a new constitution was drafted that made slavery illegal in the state.
The state of Kentucky passed two resolutions to stay neutral during the war. While the governor of Kentucky, Beriah Magoffin, believed that states should stick to the Constitution and not secede from the Union, he also refused to furnish troops to defeat the southern states. Neutrality was broken and Kentucky began to back the Union.
In Missouri, the Missouri Constitutional Convention voted to stay in the Union but refused coercion of the southern states. Secession ordinances were later adopted, although the state was never entirely under Confederate control. In 1865, the state voted to abolish slavery.
West Virginia became a state during the war when it separated from the state of Virginia. After it was established, West Virginia was considered a border state.