Of the 34 U.S. states in 1861, nineteen were free states and fifteen were slave including the four border states; each of the latter held a comparatively low percentage of slaves. Delaware never declared for secession. Maryland was largely prevented from seceding by local unionists and federal troops. Two others, Kentucky, and Missouri saw rival governments, although their territory mostly stayed in Union control. Four others did not declare for secession until after the Battle of Fort Sumter and were briefly considered to be border states: Arkansas, North Carolina, Tennessee, and Virginia. They are referred to as the Upper South. A new border state was created during the war, West Virginia, which was formed from 50 counties of Virginia and became a new state in the Union in 1863.