Sand Mountain is a sandstone plateau in northeastern Alabama and (to a far lesser extent) northwestern Georgia and southeastern Tennessee where the plateau is known as Raccoon Mountain and Elder Mountain. It is part of the southern tip of the Appalachian mountain chain and it is the largest plateau in the chain. Geologically a continuation of Walden Ridge, Sand Mountain is part of the Cumberland Plateau, separated from the main portion of the plateau by the Tennessee River and Sequatchie Valley. The average elevation on Sand Mountain is around above sea level, compared to about in the surrounding area. This elevation leads to its having the coolest climate in the state of Alabama. The largest city on Sand Mountain is Albertville, in Marshall County. As of the 2010 census, the population of the city was 21,160. History Prehistory through the Colonial Period The Sand Mountain area has been inhabited for at least 9,000 years, as evidenced by archaeological finds at nearby Russell Cave National Monument, near Bridgeport, Alabama. In historical times, Cherokee and Creek villages were located in the Tennessee Valley to the west of Sand Mountain, and in Wills Valley to the east. Sequoyah, creator of the Cherokee syllabary, lived in the Cherokee village of Wills Town, near present-day Fort Payne in Wills Valley. The first Europeans to see it were probably Spanish explorer Hernando de Soto and his men, who are believed to have crossed Sand Mountain during their journey through southeastern North America between 1539 and 1543. One of the likely routes for the expedition traces their path across Sand Mountain on the way south from the Tennessee Valley to the Coosa Valley. Civil War Union troops under Major General George H. Thomas crossed Sand Mountain in September 1863 in an attempt to cut off the Confederate troops in Chattanooga. They were unsuccessful, and the opposing armies met at the Battle of Chickamauga on September 19–20, 1863, resulting in a major Confederate victory. Jackson and DeKalb counties, along with the other counties of north Alabama, had voted against immediate secession in December 1860, and pro-Union sentiment remained strong on Sand Mountain. In early 1861, citizens in several northeastern counties proposed breaking away from Alabama and joining with neighboring counties of East Tennessee to create a new Union state of Nickajack. Industries such as mining, milling, and working for the railroad were acceptable as exemptions to military service