Southern United States
The Southern United States (also known as the Southern States or The South among Americans) is a term for the Southeastern part of the United States. All Confederate states were in the South, but not all Southern states joined the Confederacy; those that did not join were called border states. The States farthest to the south are called the "Deep South". Even though Arizona, New Mexico and southern California are  geographically southern parts of United States, they are usually classified as the Southwestern United States and not the South (the climate, culture and ethnic makeup of the Southwest are also different from the South).