| North Branch Potomac River | |
| Name Other: | Tributary to Potomac River |
| Pushpin Map: | West Virginia |
| Pushpin Map Caption: | Location of mouth |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | State |
| Subdivision Name2: | West Virginia, Maryland |
| Subdivision Type3: | County |
| Subdivision Name3: | Allegany (MD), Garrett (MD), Hampshire (WV), Mineral (WV), Grant (WV), Preston (WV) |
| Subdivision Type4: | Cities (WV) |
| Subdivision Name4: | Bayard, Gormania, Piedmont, Keyser, Cumberland |
| Subdivision Type5: | Cities (MD) |
| Subdivision Name5: | Kitzmiller, Luke, Westernport |
| Length: | 101.27miles[1] |
| Discharge1 Location: | Potomac River |
| Discharge1 Avg: | 5.13cuft/s at mouth with Potomac River[2] |
| Source1: | Blackwater River divide |
| Source1 Location: | about 1 mile northwest of Fairfax, West Virginia |
| Source1 Coordinates: | 39.1951°N -79.4892°W[3] |
| Source1 Elevation: | 2960feet |
| Mouth: | Potomac River |
| Mouth Location: | about 1 mile east of Green Spring, West Virginia |
| Mouth Coordinates: | 39.5284°N -78.5875°W |
| Mouth Elevation: | 525feet |
| Progression: | Potomac River → Chesapeake Bay → Atlantic Ocean |
| River System: | Potomac River |
| Tributaries Left: | Laurel Run, Sand Run, Nyedegger Run, Glade Run, Steyer Run, Laurel Run, Crooked Run, Lostland Run, Short Run, Three Forks Run, Stony Hollow, Elklick Run, Folly Run, Laurel Run, Savage River, Georges Creek, Stony Run, Wildcat Hollow, Culvert Hollow, Dry Run, Deep Hollow, Warrior Run, Wills Creek, Collier Run, Mill Run, Seven Springs Run |
| Tributaries Right: | Red Oak Creek, Buffalo Creek, Difficult Creek, Stony River, Maple Run, Abram Creek, Deep Run, Howell Run, Piney Swamp Run, Montgomery Run, Slaughterhouse Run, Powder House Run, Thunderhill Run, New Creek, Willow Run, Ashcabin Run, Koulip Hollow, Buckwheat Hollow, Patterson Creek, Dans Run, Round Bottom Hollow, Kern Hollow, Green Spring Run |
| Waterbodies: | Bloomington Lake |
| Bridges: | West Kempton Road (x2), Corona Bayard Road, Kitzmiller Road, Masteller Road, WV 46, US 220, Black Oak Road, WV 956, WV 28 Alt, Canal Parkway, Green Spring Road |
The North Branch Potomac River flows from Fairfax Stone in West Virginia to its confluence with the South Branch Potomac River near Green Spring, West Virginia, where it turns into the Potomac River proper.
From the Fairfax Stone, the North Branch Potomac River flows 27miles to the man-made Jennings Randolph Lake, an impoundment designed for flood control and emergency water supply. Below the dam, the North Branch cuts a serpentine path through the eastern Allegheny Mountains. First, it flows northeast by the communities of Bloomington, Luke, and Westernport in Maryland and then on by Keyser, West Virginia to Cumberland, Maryland. At Cumberland, the river turns southeast. downstream from its source, the North Branch is joined by the South Branch between Green Spring and South Branch Depot, West Virginia from whence it flows past Hancock, Maryland and turns southeast once more on its way toward Washington, D.C., and the Chesapeake Bay.
Historically, the North Branch had highly acidic water due to waste from coal mining and paper production in the region.[4] In 1969, one measuring station recorded a pH of 2.3, comparable to lemon juice.[5] This regularly killed wildlife across a span. It was somewhat mitigated by the construction of the Bloomington Dam, which allowed for flow control based on density. The dam was constructed in 1981; by 1987, the pH had returned to the neutral range in some areas, but dissolved aluminum and manganese concentrations were still at toxic levels, which continued to impede full wildlife recovery.[6] In 1990, Maryland installed lime dosers, devices which dispense alkaline lime into the river, to further mitigate acidity in problem spots.[7] This was successful, and today fish can survive in the river again.