The Eastern Continental Divide, Eastern Divide or Appalachian Divide is a hydrological divide in eastern North America that separates the easterly Atlantic Seaboard watershed from the westerly Gulf of Mexico watershed. The divide nearly spans the United States from south of Lake Ontario through the Florida peninsula, and consists of raised terrain including the Appalachian Mountains to the north, the southern Piedmont Plateau and lowland ridges in the Atlantic Coastal Plain to the south. Water including rainfall and snowfall, lakes, streams and rivers on the eastern/southern side of the divide drains to the Atlantic Ocean; water on the western/northern side of the divide drains to the Gulf of Mexico. The ECD is one of six continental hydrological divides of North America which define several drainage basins, each of which drains to a particular body of water.
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At its northern terminus, the Eastern Continental Divide originates at the Eastern Triple Divide, its intersection with the St. Lawrence Divide on a summit named Triple Divide Peak in Potter County, Pennsylvania, about south of the New York-Pennsylvania border. This point divides the eastern United States into three watersheds, those of the St. Lawrence River to the north, the Atlantic seaboard to the east, and the Gulf of Mexico to the west.
From north to south, the divide passes through the broader Allegheny Plateau region, following the boundary between the Allegheny River and Susquehanna River watersheds through most of Pennsylvania. At Blue Knob near Altoona, the Divide begins to follow Allegheny Mountain and then Little Savage Mountain. A few miles before the state border, the Divide begins to separate the Youghiogheny River and Potomac River watersheds.[1]
In Maryland, the Divide runs significantly west of the Allegheny Front, following Backbone Mountain, and passing near the source of the North Branch Potomac River at the Fairfax Stone. The Divide then passes through a plateau of the Allegheny Mountains of West Virginia, passing between the north end of the Canaan Valley in the Cheat River watershed, and the Mount Storm Lake basin in the Potomac River watershed. The Divide then rejoins the Allegheny Front.
A significant portion of the Divide forms part of the border between West Virginia and Virginia along Allegheny Mountain and then Peters Mountain, separating the Greenbrier River and James River watersheds. It then makes a dramatic arc to the east around the Sinking Creek valley, and then follows the hill crest east of Blacksburg, Virginia, until it meets the Blue Ridge Mountains, which take the form of an escarpment separating the headwaters of the New River from that of the Roanoke River.[2] [3]
Just before the Divide passes into North Carolina, it begins to separate the New River and Yadkin River watersheds. It then separates upper tributaries of the Tennessee River from those of the Santee River.[4] Its high point is on Grandfather Mountain at 5,946 feet (1,812 m); although Mount Mitchell is the highest point in the Appalachian Mountains, it is not on the Divide, but 4 miles west of it.
In Georgia, the Divide generally separates the Apalachicola River watershed in the west from the Savannah River and Altamaha River watersheds to the east, passing through the Atlanta metropolitan area and extending past the southern end of the Appalachian Mountains southeasterly across the Georgia plateau. This marks the first time the western watershed drains directly to the Gulf of Mexico without reaching the Ohio River first. In southern Georgia, it separates the Suwannee River and Satilla River watersheds.[5]
In Florida, the Divide generally follows the western edge of the St. Johns River, meandering into the low country of Northern Florida until it reaches central Florida. The southern terminus of the Eastern Continental Divide is at the northern edge of the Kissimmee River watershed, part of the Lake Okeechobee drainage basin.. The elevation here is about .
South of here, the terrain consists of low swampland covered by a network of diverging canals and natural waterways. As such, the land is not clearly divisible between the Gulf of Mexico watershed and the Atlantic watershed.
The exact route of the ECD shifts over time due to erosion, tectonic activity, construction projects, and other factors.
Because the divide is at or in proximity to the highest terrain, air is forced upwards regardless of wind direction. This process of orographic enhancement leads to higher precipitation than surrounding areas. In winter, the divide is often much snowier than surrounding areas, due to orographic enhancement and cooler temperatures with elevation.
Prior to about 1760, north of Spanish Florida, the Appalachian Divide represented the boundary between British and French colonial possessions in North America. [6] The Royal Proclamation of 1763 separated settled lands of the Thirteen Colonies from lands north and west of it designated the Indian Reserve; the proclamation border ran along the Appalachian Divide but extended beyond its Pennsylvania-New York terminus north into New England.
| Area | width=24% | Point | Summit or other feature | |
|---|---|---|---|---|
| Pennsylvania: | 2523feet 41.8467°N -77.8372°W< | --SOURCE: USGS gnispublic WEBPAGE--> | Triple Divide Peak, Ulysses Township, Potter County | |
| Pennsylvania: Interstate 80 | 41.1202°N -78.6347°W | |||
| Pennsylvania: Babcock Ridge | ||||
| Pennsylvania: Allegheny Mountain | 2167feet 40.4814°N -78.5503°W | summit near Allegheny/Gallitzin Tunnels | ||
| Pennsylvania: Allegheny Mountain | 2690feet 39.9614°N -78.8567°W | summit above Allegheny Mountain Tunnel (Pennsylvania Turnpike) | ||
| Pennsylvania: Allegheny Mountain | 2460feet 39.8103°N -78.9606°W | summit above Sand Patch Tunnel | ||
| Pennsylvania: Savage Mountain | 2392feet[7] 39.7533°N -78.9161°W | railroad cut on Great Allegheny Passage | ||
| Pennsylvania/Maryland: Savage Mountain | 2840feet 39.7225°N -78.9142°W | highest summit of the Mason–Dixon Line | ||
| Maryland: Interstate 68 | 2620feet 39.6828°N -79.0377°W | crossing near Green Lantern Road | ||
| Maryland: Savage Mountain | 2600feet 39.5075°N -79.2192°W | saddle point at planned route of 1828 C&O Canal | ||
| Maryland/West Virginia: Backbone Mountain | 3380feet 39.2375°N -79.4856°W (highest point) | Headwaters of Potomac River (Maryland's southern border) and Youghiogheny River | ||
| NaNfeet | ||||
| West Virginia: Dolly Sods Wilderness | ||||
| West Virginia: Mountain Lake Wilderness | --> | |||
| West Virginia: US Route 33 / State Route 55 | 3295feet 38.8921°N -79.4678°W | Saddle Point at Pendleton County and Randolph County. | ||
| West Virginia: Interstate 64 | 2460feet 37.7875°N -80.2245°W | Midland Trail planned crossing for the 19th century James River and Kanawha Turnpike | ||
| Virginia: Jefferson National Forest | 3620feet 37.3408°N -80.5344°W | saddle point at Johns Creek headwaters (James River tributary), and near triple point of Mississippi River (W) & Chesapeake Bay (NE)/Albemarle Sound (Roanoke River) (SE) | ||
| Virginia: Appalachian Trail | 3397feet 37.3804°N -80.3064°W | Parallel Route Begin | ||
| Virginia: Blacksburg, Virginia | 2080feet | |||
| Virginia: Appalachian Trail | 3224feet 37.3435°N -80.3646°W | Parallel Route Begin | ||
| Virginia: Interstate 81 | 2180feet 37.1287°N -80.3713°W | crossing | ||
| Virginia: Christiansburg, Virginia | 2180feet 37.0949°N -80.4456°W | 2940 Riner Rd, Christiansburg, VA 24073 | ||
| Virginia: Interstate 77 | 2860feet 36.6509°N -80.7056°W | crossing | ||
| North Carolina: U.S. Route 21 | 2692feet 36.3963°N -80.9863°W | crossing at Roaring Gap, NC | ||
| 36.3773°N -81.2207°W | triple point of New River and Yadkin/West Prong Roaring rivers | |||
| North Carolina: U.S. Route 321 at Blowing Rock, North Carolina | 3620feet 36.1184°N -81.6607°W | |||
| North Carolina: North Carolina Highway 105 | 4020feet 36.1182°N -81.8386°W | crossing | ||
| North Carolina: North Carolina Highway 226 and Blue Ridge Parkway | 2820feet 35.8527°N -82.0507°W | crossing | ||
| North Carolina: Interstate 40 | 2786feet 35.6182°N -82.263°W | crossing | ||
| North Carolina: U.S. Route 74A | 2880feet 35.4888°N -82.3583°W | crossing | ||
| North Carolina: Interstate 26 | 2130feet 35.29°N -82.4019°W | crossing | ||
| North Carolina: U.S. Route 276 | 2910feet 35.1298°N -82.6392°W | crossing | ||
| North Carolina: U.S. Route 178 | 2694feet 35.0961°N -82.8094°W | crossing, approx. 1 mile north of NC/SC border | ||
| < | --NaNfeet --> | tributary of the Tennessee River along NC/SC border dividing mountain ridges running southeast meets Santee watershed flowing into Atlantic | ||
| North Carolina–South Carolina: Sassafras Mountain | 3564feet 35.0647°N -82.7772°W | located along the South Carolina-North Carolina border in northern Pickens County, South Carolina, and southern Transylvania County, North Carolina, nearest to the town of Rosman, North Carolina | ||
| North Carolina: U.S. Route 64 | 2694feet 35.1255°N -82.9108°W | crossing | ||
| North Carolina–South Carolina: Savannah watershed | across the border of Pickens County, South Carolina & Greenville County, South Carolina, up into Transylvania County, North Carolina, Jackson County, North Carolina, and Macon County, North Carolina, to dividing mountain ridges to Tennessee River tributaries | |||
| North Carolina: North Carolina Highway 107 | 3868feet 35.1231°N -83.1164°W | crossing | ||
| North Carolina: Cowee Gap | 4199feet 35.0908°N -83.1478°W | divides Tennessee (Cullasaja) and Savannah (Chatooga) rivers | ||
| North Carolina: Highlands, North Carolina | 4100feet 35.0467°N -83.1871°W< | --elevation from "Climate" section, Coord are from Highlands' Geobox, which only has a 3832 elevation--> | Sunset Rock | |
| North Carolina: North Carolina Highway 28 | 3771feet 35.0408°N -83.2023°W | crossing | ||
| Georgia: Black Rock Mountain State Park | 3640feet< | --elev from Rock Mountain (Georgia) wikiarticle--> 34.9147°N -83.3439°W[8] | a Blue Ridge summit | |
| Georgia: ACF River Basin at Young Lick | 3809feet 34.8228°N -83.6525°W | triple point at intersection of 3 GA counties: Hiwassee (Towns Co)/Chattahoochee River (Habersham Co) on the west & on the east: Savannah River (Rabun Co) | ||
| Georgia: Altamaha watershed | triple point along border of Hall & Banks (GA) counties: Chattahoochee River-Banks (west) & Altamaha River-Hall/Savannah River-Banks (east) | |||
| Georgia: Suwanee watershed | triple point: Chattahoochee River/Suwanee Creek (west) & Altamaha River (east) | |||
| Georgia: Interstate 85 | 1280feet 34.0752°N -83.9177°W | crossing (1 of 5) | ||
| Georgia: Interstate 85 | 1120feet 33.9981°N -84.0766°W | crossing (2 of 5) | ||
| Georgia: Norcross, Georgia | 1086feet 33.9456°N -84.2126°W | through Norcross historic district | ||
| Georgia: Interstate 85 | 1050feet 33.9122°N -84.208°W | crossing (3 of 5) | ||
| Georgia: Interstate 285 | 1020feet 33.8031°N -84.25°W | crossing (1 of 2) | ||
| Georgia: Atlanta | near Dekalb Av | |||
| Georgia: Interstate 75/Interstate 85 | 1020feet 33.7524°N -84.3794°W | crossing (1 of 4 crossings of I-75/4 of 5 crossings of I-85) | ||
| Georgia: Interstate 20 | 1050feet 33.7412°N -84.4107°W | crossing | ||
| Georgia: Interstate 85 | 1000feet 33.6618°N -84.4274°W | crossing (5 of 5) | ||
| Georgia: Interstate 75 | 976feet 33.6554°N -84.3951°W | crossing (2 of 4) | ||
| Georgia: Interstate 285 | 960feet 33.631°N -84.3929°W | crossing (2 of 2) | ||
| Georgia: Interstate 75 | 927feet 33.5749°N -84.3355°W | crossing (3 of 4) | ||
| Georgia: Atlantic Seaboard fall line | near Macon, Georgia, this intersection is a triple physiographic point of the Piedmont (to the north) and the Gulf & Atlantic coastal plains (southwest & southeast). | |||
| Georgia: Interstate 75 | 410feet 32.1711°N -83.7526°W | crossing (4 of 4) | ||
| Georgia: Satilla watershed | triple point: Suwannee (west) & Altamaha River/Satilla River (east) | |||
| Georgia: St. Marys watershed | triple point: Suwannee (west) & Satilla River/St. Marys River (east) | |||
| Florida: St. Johns watershed | triple point: Suwannee (west) & St. Marys River/St. Johns River (east) | |||
| Florida: Interstate 10 | 159feet 30.2541°N -82.3994°W | crossing | ||
| Florida: Florida Trail | Central Florida crossing over the Florida crustal arch | |||
| Florida: Withlacoochee watershed | triple point: Suwannee/Withlacoochee River (Florida) (west) & St. Johns River (east) | |||
| Florida: Miami watershed | triple point: Withlacoochee (west) & St. Johns River/Miami River (east) | |||
| Florida: Kissimmee/Okeechobee watershed | south point of ECD @ Withlacoochee & Miami/Kissimmee triple point | |||