Iron Hill is a prominent geographical feature in the vicinity of

Newark Newark most commonly refers to: * Newark, New Jersey, city in the United States * Newark Liberty International Airport, New Jersey; a major air hub in the New York metropolitan area Newark may also refer to: Places Canada * Niagara-on-the ...

Delaware Delaware ( ) is a state in the Mid-Atlantic region of the United States, bordering Maryland to its south and west; Pennsylvania to its north; and New Jersey and the Atlantic Ocean to its east. The state takes its name from the adjacent Del ...

, in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. With a

topographic prominence In topography, prominence (also referred to as autonomous height, relative height, and shoulder drop in US English, and drop or relative height in British English) measures the height of a mountain or hill's summit relative to the lowest contou ...

of , it is the most prominent

hill A hill is a landform that extends above the surrounding terrain. It often has a distinct Summit (topography), summit. Terminology The distinction between a hill and a mountain is unclear and largely subjective, but a hill is universally con ...

in Delaware. However, its peak elevation of means that it is not the state's highest point, which is located in the

Piedmont it, Piemontese , population_note = , population_blank1_title = , population_blank1 = , demographics_type1 = , demographics1_footnotes = , demographics1_title1 = , demographics1_info1 = , demographics1_title2 ...

plateau region near Centreville 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 geodetic benchmark monument and has an elevation of above sea level. The only state high-point with a lower eleva ...

. The hill is named for its

iron Iron () is a chemical element with symbol Fe (from la, ferrum) 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, right in f ...

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

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 pre ...

, 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 Route 1 (US 1) in Miami, Miami, Florida, to the Houlton–Woodstock Border Crossing between M ...

and west of

Delaware Route 896 Delaware Route 896 (DE 896) is a state highway located in New Castle County, Delaware. The route runs from U.S. Route 13 (US 13) in Boyds Corner north to the Maryland border northwest of Newark, where the road becomes unsig ...

. 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

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 typically prominent where rivers cross it, with resulting rapids or waterfalls. The uplands are relatively hard crystalline basement rock, and the coa ...

and surrounded by the relatively flat

Atlantic coastal plain The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth#Surface, Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Afr ...

. 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), mafic intrusive igneous rock formed from the slow cooling of magnesium-rich and iron-rich magma into a holocrystalline mass deep beneath the Earth's surface. Slow-cooling, coarse-grained gabbro is che ...

", a coarse and dark-colored rock composed mainly of

plagioclase Plagioclase is a series of tectosilicate (framework silicate) minerals within the feldspar group. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a continuous solid solution series, more prope ...

pyroxene The pyroxenes (commonly abbreviated to ''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 calcium (Ca), sodium (Na), iron (Fe II) ...

s, and

olivine The mineral olivine () is a magnesium iron silicate with the chemical formula . It is a type of nesosilicate or orthosilicate. The primary component of the Earth's upper mantle, it is a common mineral in Earth's subsurface, but weathers quickl ...

. The rock contains significant

iron oxide Iron oxides are chemical compounds composed of iron and oxygen. Several iron oxides are recognized. All are black magnetic solids. Often they are non-stoichiometric. Oxyhydroxides are a related class of compounds, perhaps the best known of whic ...

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 FeO(OH)·H2O, although this is not entirely accurate as the ratio of oxide to hydroxid ...

, forming the basis for historical iron mining activity.

Jasper Jasper, an aggregate of microgranular quartz and/or cryptocrystalline chalcedony and other mineral phases,Kostov, R. I. 2010. Review on the mineralogical systematics of jasper and related rocks. – Archaeometry Workshop, 7, 3, 209-213PDF/ref> ...

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 Augustine Herman, First Lord of Bohemia Manor (Czech: Augustin Heřman, c. 1621 – September 1686) was a Bohemian explorer, merchant and cartographer who lived in New Amsterdam and Cecil County, Maryland. In the employment of Cecil Calvert, 2nd B ...

'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 and religious thinker belonging to the Religious Society of Friends (Quakers), and founder of the Province of Pennsylvania, a North American colony of England. He was an early advocate of democracy a ...

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 of extracting rock or minerals from the earth from an open-air pit, sometimes known as a borrow. This form of mining ...

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 a battle fought on September 3, 1777, between the Continental Army and militia (United States), American militia and primarily Hessian (soldiers), German soldiers serving a ...

(also known as the Battle of Iron Hill) in September 1777.

George Washington George Washington (February 22, 1732, 1799) was an American military officer, statesman, and Founding Father who served as the first president of the United States from 1789 to 1797. Appointed by the Continental Congress as commander of th ...

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 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. The most concentrated d ...

; 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, MD. The Principio Iron Works were started here in 1719 by Joseph Farmer with British capital and an ironmaster, John England, who made i ...

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 served on its board of director ...

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