Delaware, Kentucky, Maryland, and Missouri are the Border States that did not take sides during the Civil War.
Step-by-step explanation:
The slave states during the time of Civil War are the Border States. The Border States are the states at the Civil War of America that doesn't left the Union.
The Border States includes Kentucky, Missouri, Maryland, and Delaware. After the separation of West Virginia from Virginia, it also became a border state.
Most of the Border States had strong cultural relationships with the South, whereas they had good economic relationships with the North and the rest were devoted to the Union.