Sideling Hill, also Side Long Hill, is a long, steep, narrow mountain ridge in the

Ridge-and-Valley The Ridge-and-Valley Appalachians, also called the Ridge and Valley Province or the Valley and Ridge Appalachians, are a physiographic province of the larger Appalachian division and are also a belt within the Appalachian Mountains extending ...

(or

Allegheny Mountains The Allegheny Mountain Range (; also spelled Alleghany or Allegany), informally the Alleghenies, is part of the vast Appalachian Mountain Range of the Eastern United States and Canada and posed a significant barrier to land travel in less devel ...

) physiographic province of the

Appalachian Mountains The Appalachian Mountains, often called the Appalachians, (french: Appalaches), are a system of mountains in eastern to northeastern North America. The Appalachians first formed roughly 480 million years ago during the Ordovician Period. The ...

, located in Washington County in western

Maryland Maryland ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; ...

and adjacent

West Virginia West Virginia is a state in the Appalachian, Mid-Atlantic and Southeastern regions of the United States.The Census Bureau and the Association of American Geographers classify West Virginia as part of the Southern United States while the ...

and

Pennsylvania Pennsylvania (; (Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, Ma ...

, USA. The highest point on the ridge is Fisher Point, at in

Fulton County, Pennsylvania Fulton County is a county in the Commonwealth of Pennsylvania. As of the 2020 census, the population was 14,556, making it the fourth-least populous county in Pennsylvania. Its county seat is McConnellsburg. The county was created on April 19, ...

Geology

Sideling Hill is a syncline mountain, in a region of downward-folded ( synclinal)

rock strata In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as e ...

between two upfolded

anticline In structural geology, an anticline is a type of fold that is an arch-like shape and has its oldest beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex up in which the hinge or crest is the ...

s. The ridge is capped by an erosion-resistant

conglomerate Conglomerate or conglomeration may refer to: * Conglomerate (company) * Conglomerate (geology) * Conglomerate (mathematics) In popular culture: * The Conglomerate (American group), a production crew and musical group founded by Busta Rhymes ** Co ...

and

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

Mississippian Mississippian may refer to: * Mississippian (geology), a subperiod of the Carboniferous period in the geologic timescale, roughly 360 to 325 million years ago *Mississippian culture, a culture of Native American mound-builders from 900 to 1500 AD ...

(early Carboniferous) geologic age, the Purslane Sandstone of the Pocono Formation. The ridge's slopes are formed of much more easily eroded kinds of rock, including the

Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, w ...

Rockwell Formation, with long, narrow valleys paralleling the ridge on either side.

Ecology

Most of the crest of Sideling Hill is forested, primarily with various

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, a ...

tree species such as oaks (''Quercus'') and hickories (''Carya''), along with occasional

evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, which ...

pines (''Pinus'').

Highway, railroad, and canal crossings

Only a few major highways, one active and two former railroads, and one former canal cross this steep mountain ridge.

East Broad Top Railroad Tunnel (Pennsylvania)

The

East Broad Top Railroad The East Broad Top Railroad (EBT) is a narrow gauge historic and heritage railroad headquartered in Rockhill Furnace, Pennsylvania. Operating from 1871 to 1956, it is one of the nation's oldest and best-preserved narrow-gauge railroad ...

constructed a

tunnel A tunnel is an underground passageway, dug through surrounding soil, earth or rock, and enclosed except for the entrance and exit, commonly at each end. A pipeline is not a tunnel, though some recent tunnels have used immersed tube cons ...

through Sideling Hill in 1873–1874 as part of its mainline construction. The tunnel predates the

South Pennsylvania Railroad The South Pennsylvania Railroad is the name given to two proposed, but never completed, Pennsylvania railroads in the nineteenth century. Parts of the right of way for the second South Pennsylvania Railroad were reused for the Pennsylvania Turnpik ...

tunnel construction to the south by eight years. The tunnel is single-tracked, and curved at each end. It originally had a stone portal on its eastern (RR North) end and a natural stone portal at its western (RR South) end, but about 1919 the north portal was replaced with a concrete one. The north portal was equipped with doors to prevent wind from blowing through the tunnel as the wind caused water percolating into the tunnel to freeze on the tracks in the winter. In 1911, this ice caused the brand new locomotive #12 to derail its pilot axle inside the tunnel then derail the entire locomotive at the Kimmel switch just beyond the tunnel. In the 1940s, the doors were equipped with remote actuators mounted on poles a few hundred feet before each portal. This allowed the crews to open and close the doors without stopping. The system did not work flawlessly and a door was ripped off by a

caboose A caboose is a crewed North American railroad car coupled at the end of a freight train. Cabooses provide shelter for crew at the end of a train, who were formerly required in switching and shunting, keeping a lookout for load shifting, dama ...

cupola. The tunnel was in service from 1874 until the railroad ceased operations in 1956. The line is technically out of service (but not abandoned), and the track is still in place through the tunnel, although not serviceable. The tunnel and rail line are private property and not open to the public.

Pennsylvania Turnpike (I-76)

The

Pennsylvania Turnpike The Pennsylvania Turnpike (Penna Turnpike or PA Turnpike) is a toll highway operated by the Pennsylvania Turnpike Commission (PTC) in the U.S. state of Pennsylvania. A controlled-access highway, it runs for across the state. The turnpike's ...

( Interstate 76, I-76) crosses Sideling Hill east of Breezewood, Pennsylvania, bypassing the two-lane Sideling Hill Tunnel and the nearby Rays Hill Tunnel that were formerly used by the Turnpike. Completed at a cost of $17,203,000, the Sideling Hill bypass opened on November 26, 1968, and the former alignment through the tunnels became known as the

Abandoned Pennsylvania Turnpike The Abandoned Pennsylvania Turnpike is the common name of a stretch of the Pennsylvania Turnpike that was bypassed in 1968 when a modern stretch opened to ease traffic congestion in the tunnels. In this case, the Sideling Hill Tunnel and Rays H ...

. A rest area next to the ridge was a stop on Bill Clinton and Al Gore's post-convention bus tour in 1992.

Sideling Hill Tunnel (Pennsylvania)

The Sideling Hill Tunnel, through Sideling Hill in

east of Breezewood, is currently in its third phase of life. In the 1880s, a tunnel was partially bored through the mountain by the

. The railroad project ceased, and the tunnel was left abandoned. When construction of the

was begun in the 1930s by the

Pennsylvania Turnpike Commission The Pennsylvania Turnpike Commission (PTC) is an agency created in 1937 to construct, finance, operate, and maintain the Pennsylvania Turnpike (both the mainline and the Northeast Extension). The commission consists of five members. Four membe ...

on the

right-of-way Right of way is the legal right, established by grant from a landowner or long usage (i.e. by prescription), to pass along a specific route through property belonging to another. A similar ''right of access'' also exists on land held by a gov ...

of the South Pennsylvania Railroad, the tunnel was completed for highway use by the turnpike. The tunnel, the longest of the seven original turnpike tunnels at long, was used from the turnpike's opening in 1940 until 1968. Due to increasing traffic on the highway, the turnpike commission began upgrading all of its two-lane tunnels, constructing twin bores for its tunnels through the Allegheny, Tuscarora, Kittatinny, and Blue mountains, and bypassing the tunnels under Laurel Hill, Rays Hill, and Sideling Hill with new, six-lane highways climbing the adjacent hills. The Sideling Hill Tunnel and the nearby Rays Hill tunnel, along with connecting segments of four-lane highway, were used for many years as a testing facility for new highway technologies. In 2001, the Sideling Hill Tunnel was sold to the Southern Alleghenies Conservancy for $1, which now operates it as a bike trail.

Sideling Hill Road Cut (I-68 and US 40, Maryland)

The Sideling Hill Road Cut on I-68 and

US 40 U.S. Route 40 or U.S. Highway 40 (US 40), also known as the Main Street of America, is a major east–west United States Highway traveling across the United States from the Mountain States to the Mid-Atlantic States. As with most routes w ...

is a notch excavated from the ridge of Sideling Hill, about west of Hancock in

Washington County, Maryland Washington County is located in the Western Maryland, western part of the U.S. state of Maryland. As of the 2020 United States census, 2020 census, the population was 154,705. Its county seat is Hagerstown, Maryland, Hagerstown. Washington Coun ...

. Blasting was completed in August 1984. It is notable as an impressive man-made mountain pass, visible from miles away, and is considered to be one of the best rock exposures in Maryland and the entire northeastern United States. Almost of

strata In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as e ...

in a tightly folded

syncline In structural geology, a syncline is a fold with younger layers closer to the center of the structure, whereas an anticline is the inverse of a syncline. A synclinorium (plural synclinoriums or synclinoria) is a large syncline with superimposed ...

are exposed in this road cut. Although other exposures may surpass Sideling Hill in either thickness of exposed strata or in quality of geologic structure, few can equal its combination of both. The exposed rocks consist of the

Rockwell Formation, underlying the Mississippian Purslane Sandstone.

Rest stop and former exhibit center

A highway rest stop, located near the eastern side of the Sideling Hill Road Cut on I-68 west of Hancock, includes a pedestrian bridge crossing I-68, connecting the eastbound and westbound rest areas and offering views of the cut, in which stopping is prohibited. The rest stop formerly included the Sideling Hill Exhibit Center, a four-level geological museum and travel information center which opened in 1991. Due to state budget cuts, this facility was closed on August 15, 2009, as part of a $280 million budget reduction package, saving the state about $110,000 annually. Before its closing, the center served about 95,000 visitors a year. Many of the geological exhibits from the former Exhibit Center are now displayed at the Hancock Museum in nearby

Hancock, Maryland Hancock is a town in Washington County, Maryland, United States. The population was 1,546 at the 2010 census. The Western Maryland community is notable for being located at the narrowest part of the state. The north-south distance from the Penns ...

. The former exhibit center building was reopened as a welcome center on October 9, 2015. Only part of the facility is open, with the former exhibit center exhibits remaining at the Hancock Museum.

National Road (US 40 Scenic)

Before construction of I-68, US 40 (now US 40 Scenic), the

National Road The National Road (also known as the Cumberland Road) was the first major improved highway in the United States built by the Federal Government of the United States, federal government. Built between 1811 and 1837, the road connected the Pot ...

, crossed Sideling Hill with a steep grade on each side and a sharp

hairpin turn A hairpin turn (also hairpin bend or hairpin corner) is a bend in a road with a very acute inner angle, making it necessary for an oncoming vehicle to turn about 180° to continue on the road. It is named for its resemblance to a bent metal ha ...

at the crest of the mountain.

Potomac River Water Gap

The

water gap A water gap is a gap that flowing water has carved through a mountain range or mountain ridge and that still carries water today. Such gaps that no longer carry water currents are called wind gaps. Water gaps and wind gaps often offer a pra ...

cut through Sideling Hill by the

Potomac River The Potomac River () drains the Mid-Atlantic (United States), Mid-Atlantic United States, flowing from the Potomac Highlands of West Virginia, Potomac Highlands into Chesapeake Bay. It is long,U.S. Geological Survey. National Hydrography Datas ...

southwest (upstream) of

, provides a low-level crossing of the ridge for the CSX Railroad, formerly the main line of the Baltimore and Ohio (B&O) Railroad, on the southern (West Virginia) side of the river, and on the northern (Maryland) side, the former

Chesapeake and Ohio Canal The Chesapeake and Ohio Canal, abbreviated as the C&O Canal and occasionally called the "Grand Old Ditch," operated from 1831 until 1924 along the Potomac River between Washington, D.C. and Cumberland, Maryland. It replaced the Potomac Canal, wh ...

, now a

national historical park National Historic Site (NHS) is a designation for an officially recognized area of national historic significance in the United States. An NHS usually contains a single historical feature directly associated with its subject. The National Historic ...

, and the former Western Maryland Railroad (now a

rail trail A rail trail is a shared-use path on railway right of way. Rail trails are typically constructed after a railway has been abandoned and the track has been removed, but may also share the right of way with active railways, light rail, or streetca ...

References

External links

* {{Authority control Ridges of Hampshire County, West Virginia Ridges of Morgan County, West Virginia Landforms of Washington County, Maryland Landforms of Allegany County, Maryland Ridges of Maryland Ridges of Pennsylvania Ridges of West Virginia Valleys of Maryland Water gaps of the United States Landforms of Fulton County, Pennsylvania Ridges of Huntingdon County, Pennsylvania