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Iron Hill is a prominent geographical feature in the vicinity of Newark,
Delaware Delaware ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic and South Atlantic states, South Atlantic regions of the United States. It borders Maryland to its south and west, Pennsylvania to its north, New Jersey ...
, in the
United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
. With a
topographic prominence In topography, prominence or relative height (also referred to as autonomous height, and shoulder drop in US English, and drop in British English) measures the height of a mountain or hill's summit relative to the lowest contour line encircling ...
of , it is the most prominent
hill A hill is a landform that extends above the surrounding terrain. It often has a distinct summit, and is usually applied to peaks which are above elevation compared to the relative landmass, though not as prominent as Mountain, mountains. Hills ...
in Delaware. However, its peak elevation of means that it is not the state's highest point, which is located in the
Piedmont Piedmont ( ; ; ) is one of the 20 regions of Italy, located in the northwest Italy, Northwest of the country. It borders the Liguria region to the south, the Lombardy and Emilia-Romagna regions to the east, and the Aosta Valley region to the ...
plateau region near
Centreville Centreville is a census-designated place (CDP) in Fairfax County, Virginia, United States. It is a suburb of Washington, D.C., the nation's capital. It had a population of 73,518, making it the most-populous community in Fairfax County as of t ...
where a peak elevation of is attained at
Ebright Azimuth The Ebright Azimuth is the point with the highest benchmark monument elevation in the U.S. state of Delaware. It is marked with a Geodesy, geodetic benchmark monument and has an elevation of above sea level. The only state high-point with a lo ...
. The hill is named for its
iron Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...
deposits, which were mined over a 200-year period during the 18th and 19th centuries. It is part of a
New Castle County New Castle County is the northernmost of the three counties of the U.S. state of Delaware (New Castle, Kent, and Sussex). As of the 2020 census, the population was 570,719, making it the most populous county in Delaware, with nearly 60% of the ...
park known as Iron Hill Park.


Location

Iron Hill is located just south of Newark in
Pencader Hundred Pencader Hundred is an unincorporated subdivision of New Castle County, Delaware. Hundreds were once used as a basis for representation in the Delaware General Assembly, and while their names still appear on all real estate transactions, they p ...
, with the summit lying south of
Interstate 95 Interstate 95 (I-95) is the main north–south Interstate Highway on the East Coast of the United States, running from U.S. Route 1 (US 1) in Miami, Florida, north to the Houlton–Woodstock Border Crossing between Maine and the ...
and west of
Delaware Route 896 Delaware Route 896 (DE 896) is a state highway located in New Castle County, Delaware, New Castle County, Delaware. The route runs from U.S. Route 13 in Delaware, U.S. Route 13 (US 13) in Boyds Corner, Delaware, Boyds Corner ...
. It is the easternmost and highest of three geologically similar peaks, together with neighboring Chestnut Hill and Gray's Hill (across the border in Maryland).


Geology

Iron Hill and the two neighboring hills are outlying
Piedmont Piedmont ( ; ; ) is one of the 20 regions of Italy, located in the northwest Italy, Northwest of the country. It borders the Liguria region to the south, the Lombardy and Emilia-Romagna regions to the east, and the Aosta Valley region to the ...
outcroppings, east of the
fall line A fall line (or fall zone) is the area where an upland region and a coastal plain meet and is noticeable especially the place rivers cross it, with resulting rapids or waterfalls. The uplands are relatively hard crystalline basement rock, and the ...
and surrounded by the relatively flat
Atlantic coastal plain The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...
. The hills are igneous
intrusion In geology, an igneous intrusion (or intrusive body or simply intrusion) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and com ...
s of "Iron Hill
Gabbro Gabbro ( ) is a phaneritic (coarse-grained and magnesium- and iron-rich), mafic intrusive igneous rock formed from the slow cooling magma into a holocrystalline mass deep beneath the Earth's surface. Slow-cooling, coarse-grained gabbro is ch ...
", a coarse and dark-colored rock composed mainly of
plagioclase Plagioclase ( ) is a series of Silicate minerals#Tectosilicates, tectosilicate (framework silicate) minerals within the feldspar group. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a continu ...
,
pyroxene The pyroxenes (commonly abbreviated Px) are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents ions of calcium (Ca), sodium (Na), iron ( ...
s, and
olivine The mineral olivine () is a magnesium iron Silicate minerals, silicate with the chemical formula . It is a type of Nesosilicates, nesosilicate or orthosilicate. The primary component of the Earth's upper mantle (Earth), upper mantle, it is a com ...
. The rock contains significant
iron oxide An iron oxide is a chemical compound composed of iron and oxygen. Several iron oxides are recognized. Often they are non-stoichiometric. Ferric oxyhydroxides are a related class of compounds, perhaps the best known of which is rust. Iron ...
deposits in the form of
hematite Hematite (), also spelled as haematite, is a common iron oxide compound with the formula, Fe2O3 and is widely found in rocks and soils. Hematite crystals belong to the rhombohedral lattice system which is designated the alpha polymorph of . ...
,
goethite Goethite (, ) is a mineral of the diaspore group, consisting of iron(III) oxide-hydroxide, specifically the α- polymorph. It is found in soil and other low-temperature environments such as sediment. Goethite has been well known since ancient t ...
, and
limonite Limonite () is an iron ore consisting of a mixture of hydrated iron(III) oxide-hydroxides in varying composition. The generic formula is frequently written as , although this is not entirely accurate as the ratio of oxide to hydroxide can vary qu ...
, forming the basis for historical iron mining activity.
Jasper Jasper, an aggregate of microgranular quartz and/or cryptocrystalline chalcedony and other mineral phases, is an opaque, impure variety of silica, usually red, yellow, brown or green in color; and rarely blue. The common red color is due to ...
is also present and was used for toolmaking by prehistoric inhabitants of the area.


Magnetic influence

The slight magnetic effect due to the iron oxides in the jasper rock within Iron Hill can cause inaccuracies in compass readings.


History

Human activity in the area dates to prehistoric times, when Native Americans quarried jasper from Iron Hill to make arrowheads and other stone tools. The location was first referred to in print on Augustine Herman's 1670 map of Virginia and Maryland, where it was labeled "Yron Hill". In 1701, the hill was included in the Welsh Tract, granted by
William Penn William Penn ( – ) was an English writer, religious thinker, and influential Quakers, Quaker who founded the Province of Pennsylvania during the British colonization of the Americas, British colonial era. An advocate of democracy and religi ...
to a group of settlers fleeing religious persecution in Wales. The Welsh settlers were familiar with ironworking and mining techniques, and soon commenced
open-pit mining Open-pit mining, also known as open-cast or open-cut mining and in larger contexts mega-mining, is a surface mining technique that extracts rock (geology), rock or minerals from the earth. Open-pit mines are used when deposits of commercially ...
operations on Iron Hill. During the Revolutionary War, Iron Hill and the surrounding area were the site of the
Battle of Cooch's Bridge The Battle of Cooch's Bridge, also known as the Battle of Iron Hill, was fought on September 3, 1777, between the Continental Army and militia (United States), American militia and primarily Hessian (soldiers), German soldiers serving alongside ...
(also known as the Battle of Iron Hill) in September 1777.
George Washington George Washington (, 1799) was a Founding Fathers of the United States, Founding Father and the first president of the United States, serving from 1789 to 1797. As commander of the Continental Army, Washington led Patriot (American Revoluti ...
ascended the hill to observe enemy troop movements prior to the battle, which was possible at the time due to
deforestation Deforestation or forest clearance is the removal and destruction of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. Ab ...
; subsequent regrowth has since obscured the view from the summit. Mining on Iron Hill continued until the late 19th century, though extraction of the low-grade ore proved minimally profitable and many of the ventures ended in bankruptcy. The last mining operation on Iron Hill was run by J.P. Whitaker, who shipped the ore to
Principio Furnace Principio Furnace and village is in Cecil County, Maryland, 4 miles (6.4 km) northeast of Havre de Grace. The Principio Iron Works were started here in 1719 by Joseph Farmer with British capital and an ironmaster, John England. By the 1740s ...
in Maryland for smelting. African-American mine workers and their descendants continued to inhabit the area and, in 1923,
Pierre S. du Pont Pierre Samuel du Pont (; January 15, 1870 – April 4, 1954) was an American entrepreneur, businessman, philanthropist and member of the prominent du Pont family. He was president of DuPont from 1915 to 1919, and was on its board of directors un ...
funded the construction of Iron Hill School No. 112C to serve this population. The school remained in operation until Delaware public schools were desegregated in 1965 and now houses the Iron Hill Museum. Much of the hill is now a wooded recreation area, Iron Hill Park.


References

{{Protected Areas of Delaware Hills of the United States Landforms of New Castle County, Delaware Protected areas of New Castle County, Delaware Geology of Delaware Newark, Delaware IUCN Category III