North Georgia is the northern hilly/mountainous region in the U.S. state of Georgia. At the time of the arrival of settlers from Europe, it was inhabited largely by the Cherokee. The counties of north Georgia were often scenes of important events in the history of Georgia. It was the site of many American Civil War battles, including the Battle of Lookout Mountain and the Battle of Chickamauga, leading up to the Atlanta Campaign. Today, particularly in the northeast portion of the region, tourism sustains the local economy. Geography North Georgia encompasses the north Georgia mountains (far northeast and northwest) region of the state and the Atlanta metropolitan area, although the term is often used to describe only the region north of the metro area, especially in newscasts from the Atlanta media market (which reach nearly all of the northern third of the state). To the south lies central Georgia, with upstate South Carolina to the east, western North Carolina to the northeast, East Tennessee to the north, and northeast Alabama to the west. Part of metropolitan Chattanooga extends into the far northwestern section of Georgia from Tennessee, while most of the rest of the region is tied to Atlanta-area mass media. The highest of Georgia's Appalachian Mountains are near the North Carolina border, including Brasstown Bald, the highest point in the state. The northwest contains part of the eastern Tennessee seismic zone, and small earthquakes have been felt as far away as Atlanta. The foothills gradually flatten out toward the south. Much of metro Atlanta is hilly as well, especially on the north and west. Major rivers include the upper Chattahoochee River, upper Savannah River, Etowah River, far upper Flint River, upper Coosa River, and upper Oconee River. Smaller tributary rivers are the Little River, Chestatee River, Chattooga River, Tallulah River, Tugalo River, Oostanaula River, Coosawattee River, Cartecay River, Ellijay River, Conasauga River, Toccoa River, Sweetwater Creek, upper Tallapoosa River, upper Yellow River, Nottely River, and small headwaters of the far upper Hiawassee River and Little Tennessee River. Were it not for a 19th-century surveying error that failed to place the state's northern border at exactly 35°N, it would also touch the Tennessee River. Climate Throughout North Georgia, average temperatures can change drastically at elevations of or more above sea level. At these elevations the average summer (from May 31 to September 30) temperature is about during the afternoon and