The Blue Ridge, or Blue Ridge Mountains, is a physiographic province of the larger Appalachian division. The province consists of the Northern and Southern physiographic sections, which divide near the Roanoke River gap. They are a mountain chain in the eastern United States, part of the Appalachian Mountains, forming their eastern front from Georgia to Pennsylvania. To the west of the Blue Ridge, between it and the bulk of the Appalachians, lies the Great Valley, bordered on the west by the Ridge and Valley province. The mountains are well known for their bluish color when seen from a distance. Trees put the "blue" in Blue Ridge, from the hydrocarbons released into the atmosphere, thereby contributing to the characteristic haze on the mountains and their distinctive color.
Within the Blue Ridge province, there are two National Parks: the Shenandoah in the northern section and the Great Smoky Mountains in the southern section. The Blue Ridge also contains the Blue Ridge Parkway, a long scenic highway that connects the two parks and is located along the ridge crestlines along the Appalachian Trail.
The Blue Ridge extends as far north into Pennsylvania as South Mountain. While South Mountain dwindles to mere hills between Gettysburg and Harrisburg, the band of ancient rocks that forms the core of the Blue Ridge continues northeast through the New Jersey and Hudson River highlands, eventually reaching The Berkshires of Massachusetts and the Green Mountains of Vermont.
The Blue Ridge contains the highest mountains in eastern North America. About 125 peaks exceed in elevation. The highest peak in the Blue Ridge (and in the entire Appalachian chain) is Mt. Mitchell in North Carolina at . There are 39 peaks in North Carolina and Tennessee higher than ; by comparison, only New Hampshire's Mt. Washington rises above in the northern portion of the Appalachian chain.
The Blue Ridge Parkway runs 469 miles (750 km) along crests of the Southern Appalachians and links two national parks: Shenandoah and Great Smoky Mountains. In many places along the parkway, there are metamorphic rocks (gneiss) with folded bands of light-and dark-colored minerals, which sometimes look like the folds and swirls in a marble cake.
Many of the features found in the Blue Ridge and documented by Tollo and others have confirmed that the rocks exhibit many similar features in other North American Grenville-age terranes. The lack of a calc-alkaline affinity and zircon ages less than 1,200 Ma suggest that Blue Ridge are unique from the Adirondacks, Green Mountains, and possibly the New York-New Jersey Highlands. The petrologic and geochronologic data suggest that the Blue Ridge basement is a composite orogenic crust that was emplaced during several episodes from a crustal magma source. Field relationships further illustrate that rocks emplaced prior to 1,078-1,064 Ma preserve deformational features. Those emplaced post-1,064 Ma generally have a massive texture and missed the main episode of Mesoproterozoic compression.
At the foot of the Blue Ridge, various tribes including the Siouan Manahoacs, the Iroquois, and the Shawnee hunted and fished. As more settlers moved into Virginia, their economic and at times martial competition pushed the native inhabitants west.