The official West and East South Central states of Texas, Arkansas, Louisiana, Mississippi, Alabama and Tennessee would secede from the Union and join the Confederacy during the Civil War. Kentucky was a border state that remained with the Union. Oklahoma, although Indian Territory at the time, was home to five major Native-American tribes, of which the majority allied themselves with the Confederacy. Oklahoma territory and Indian Territory would merge into the State of Oklahoma, when it became the 46th U.S. state in 1907. All of these states are usually considered to make up a larger part of the American South, both historically and culturally, as well as classified by the U.S. Census Bureau.