Tennessee is a long, narrow state. Shaped roughly like a parallelogram, it is 500 miles from east to west, and 110 miles from north to south. Partly due to its unusual shape, Tennessee, along with Missouri, borders more states than any other in the country. Its neighbors are North Carolina, Virginia, Kentucky, Missouri, Arkansas, Mississippi, Alabama, and Georgia. Tennessee is the thirty-sixth largest state in the United States, with a land mass of 44,169 square miles.

Like the rest of the United States, some 500 million years ago Tennessee was covered by a large shallow sea. As the sea dried up, the land that is now Tennessee turned swampy and eventually dry. The sea creatures that once lived in the sea died, their skeletons forming limestone. The plants and animals that lived in the swampy landscape died, eventually forming coal.

Beginning about 600 million years ago, the Appalachian Mountains were formed through plate movement. Once sharp and rocky, the Appalachians have been worn down over millions of years to the gentle, rounded slopes that now characterize the range.