Eastern Continental Divide
The Eastern Continental Divide or Eastern Divide or Appalachian Divide is a hydrographic 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 hydrographic divides of North America which define several drainage basins, each of which drains to a particular body of water.
The divide originates at the Eastern Triple Divide near the middle of the northern border of Pennsylvania then runs generally south-by-southwest following the crest of the Appalachian Mountains through Pennsylvania, western Maryland, West Virginia, Virginia and North Carolina to its high point on Grandfather Mountain, then descends to the city of Atlanta in northwestern Georgia, where it doglegs southeasterly across the Georgia plateau and through the lowlands of Northern Florida to its terminus in central Florida at the northern boundary of the Lake Okeechobee Basin.
Though the divide is often associated with high elevation, at its southern terminus at the northern Kissimmee River watershed in Florida, the elevation is only 70ft. above sea level. Nor does the divide always coincide with the highest point or ridgeline, because streams can flow through passes or gaps in the ridge, so that terrain on one side of the ridge drains to the other side and therefore to the other watershed. This occurs in several places. The ECD is not completely fixed, but can shift due to erosion, tectonic shift and also anthropogenic activity such as tunnel excavation, damming of rivers and road construction.
In colonial times, except for Spanish Florida, the ECD served as the boundary between English colonies on the Atlantic seaboard and Indian lands to the interior.
Description
The Eastern Triple Divide is the northern terminus of the Eastern Continental Divide where it intersects the northeasterly St. Lawrence Divide near the middle of the northern border of Pennsylvania. That point divides the eastern United States into three watersheds, where the associated nearby headwaters form the Pine Creek tributary of West Branch Susquehanna River that drains to the Atlantic ocean, the Allegheny River tributary of the Ohio River that drains to the Gulf of Mexico, and the Genesee River tributary of Lake Ontario that drains to the Gulf of Saint Lawrence.
The Eastern Continental Divide originates in the north at the Eastern Triple Divide on the summit named 'Triple Divide Peak' 10.4 mi south of the New York-Pennsylvania line about 5 mi. southwest of the borough of Ulysses in Potter County, Pennsylvania. That summit is the northernmost peak of three atop a broad plateau which is currently farmland. From there, the ECD runs south-southwest through the two nearby southern summits then southwesterly along the Allegheny Plateau west of the Allegheny Front until it plunges south along the Appalachians barrier ridge. Mount Mitchell State Park in North Carolina is the highest point on the ECD at 6,366 ft. As the altitude of the peaks diminishes across the swampy Georgia plateau, the divide meanders into the low country of Northern Florida until it reaches central Florida, ending at the north bank watershed of the Kissimmee River.
While notionally, the ECD may be considered to extend to the southern tip of Florida, south of Lake Okeechobee the everglades, which spans the length and breadth of the peninsula, is a seasonal swamp which drains into the lake. During the wet season, overflow from the lake forms an unchanneled "river" 100 miles long and 60 miles wide that flows south to Florida Bay which ostensibly drains into the Gulf of Mexico, but due to mud dykes, little exchange of water actually occurs. So hydrographically, the only divide in southern Florida is between the lake and the ocean or Gulf, and that divide is coincident with the boundary between land and sea.
Because the divide represents 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.
The Lake Okeechobee drainage basin in south central Florida, including the Kissimmee River drainage basin to the north which feeds it, was naturally or hydrographically, an endorheic basin, one which does not have outflow to another body of water like a river or ocean. Such a basin may form a swamp when water collects. It was altered by anthropogenic activity, specifically the construction of the Okeechobee canal in 1937 which spanned the Atlantic Ocean, the lake and the Gulf of Mexico. Nonetheless, it is not considered by hydrologists to be part of either the Gulf of Mexico watershed or Atlantic seaboard watershed. The northern boundary of the basin is the southern terminus of the Eastern Continental divide.
History
Prior to about 1760, north of Spanish Florida, the Appalachian Divide represented the boundary between British and French colonial possessions in North America.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.
Locations
| Area | Point | Summit or other feature |
| Pennsylvania: | Triple Divide Peak, Ulysses Township, Potter County | |
| Pennsylvania: Babcock Ridge | ||
| Pennsylvania: Allegheny Mountain | summit near Allegheny/Gallitzin Tunnels | |
| Pennsylvania: Allegheny Mountain | summit above Allegheny Mountain Tunnel | |
| Pennsylvania: Allegheny Mountain | summit above Sand Patch Tunnel | |
| Pennsylvania: Savage Mountain | railroad cut on Great Allegheny Passage | |
| Pennsylvania/Maryland: Savage Mountain | highest summit of the Mason–Dixon Line | |
| Maryland: Interstate 68 | crossing near Green Lantern Road | |
| Maryland: Savage Mountain | saddle point at planned route of 1828 C&O Canal | |
| Maryland/West Virginia: Backbone Mountain | Headwaters of Potomac River and Youghiogheny River | |
| West Virginia: US Route 33 / State Route 55 | Saddle Point at Pendleton County and Randolph County. | |
| West Virginia: Interstate 64 | Midland Trail: planned crossing for the 19th century James River and Kanawha Turnpike | |
| Virginia: Jefferson National Forest | saddle point at Johns Creek headwaters, and near triple point of Mississippi River & Chesapeake Bay /Albemarle Sound | |
| Virginia: Appalachian Trail | Parallel Route Begin | |
| Virginia: Blacksburg, Virginia | ||
| Virginia: Appalachian Trail | Parallel Route Begin | |
| Virginia: Interstate 81 | crossing | |
| Virginia: Christiansburg, Virginia | 2940 Riner Rd, Christiansburg, VA 24073 | |
| Virginia: Interstate 77 | crossing | |
| North Carolina: U.S. Route 21 | crossing at Roaring Gap, NC | |
| triple point of New River and Yadkin/West Prong Roaring rivers | ||
| North Carolina: North Carolina Highway 105 | crossing | |
| North Carolina: North Carolina Highway 226 and Blue Ridge Parkway | crossing | |
| North Carolina: Interstate 40 | crossing | |
| North Carolina: U.S. Route 74A | crossing | |
| North Carolina: Interstate 26 | crossing | |
| North Carolina: U.S. Route 276 | crossing | |
| North Carolina: U.S. Route 178 | crossing, approx. 1 mile north of NC/SC border | |
| 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 | 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 | 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: Highlands, North Carolina | Sunset Rock | |
| North Carolina: North Carolina Highway 28 | crossing | |
| North Carolina: Cowee Gap | divides Tennessee and Savannah rivers | |
| Georgia: Black Rock Mountain State Park | a Blue Ridge summit | |
| Georgia: ACF River Basin at Young Lick | triple point at intersection of 3 GA counties: Hiwassee /Chattahoochee River on the west & on the east: Savannah River | |
| Georgia: Altamaha watershed | triple point along border of Hall & Banks counties: Chattahoochee River-Banks & Altamaha River-Hall/Savannah River-Banks | |
| Georgia: Suwanee watershed | triple point: Chattahoochee River/Suwanee Creek & Altamaha River | |
| Georgia: Interstate 85 | crossing | |
| Georgia: Interstate 85 | crossing | |
| Georgia: Norcross, Georgia | through Norcross historic district | |
| Georgia: Interstate 85 | crossing | |
| Georgia: Interstate 285 | crossing | |
| Georgia: Atlanta | near Dekalb Av | |
| Georgia: Interstate 75/Interstate 85 | crossing | |
| Georgia: Interstate 20 | crossing | |
| Georgia: Interstate 85 | crossing | |
| Georgia: Interstate 75 | crossing | |
| Georgia: Interstate 285 | crossing | |
| Georgia: Interstate 75 | crossing | |
| Georgia: Atlantic Seaboard fall line | near Macon, Georgia, this intersection is a triple physiographic point of the Piedmont and the Gulf & Atlantic coastal plains. | |
| Georgia: Interstate 75 | crossing | |
| Georgia: Satilla watershed | triple point: Suwannee & Altamaha River/Satilla River | |
| Georgia: St. Marys watershed | triple point: Suwannee & Satilla River/St. Marys River | |
| Florida: St. Johns watershed | triple point: Suwannee & St. Marys River/St. Johns River | |
| Florida: Interstate 10 | crossing | |
| Florida: Florida Trail | Central Florida crossing over the Florida crustal arch | |
| Florida: Withlacoochee watershed | triple point: Suwannee/Withlacoochee River & St. Johns River | |
| Florida: Miami watershed | triple point: Withlacoochee & St. Johns River/Miami River | |
| Florida: Kissimmee/Okeechobee watershed | south point of ECD @ Withlacoochee & Miami/Kissimmee triple point |