The Twelve-Mile Circle
Encyclopedia
Pennsylvania
The Commonwealth of Pennsylvania is a U.S. state that is located in the Northeastern and Mid-Atlantic regions of the United States. The state borders Delaware and Maryland to the south, West Virginia to the southwest, Ohio to the west, New York and Ontario, Canada, to the north, and New Jersey to...
and the State of Delaware
Delaware
Delaware is a U.S. state located on the Atlantic Coast in the Mid-Atlantic region of the United States. It is bordered to the south and west by Maryland, and to the north by Pennsylvania...
in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. It is not actually a circle, but rather a combination of different circular arcs that have been imperceptibly feathered together.
It is nominally a circle
Circle
A circle is a simple shape of Euclidean geometry consisting of those points in a plane that are a given distance from a given point, the centre. The distance between any of the points and the centre is called the radius....
with a supposed—yet in fact only approximate and variable—twelve-mile radius
Radius
In classical geometry, a radius of a circle or sphere is any line segment from its center to its perimeter. By extension, the radius of a circle or sphere is the length of any such segment, which is half the diameter. If the object does not have an obvious center, the term may refer to its...
, centered in the town of New Castle, Delaware
New Castle, Delaware
New Castle is a city in New Castle County, Delaware, six miles south of Wilmington, situated on the Delaware River. In 1900, 3,380 people lived here; in 1910, 3,351...
. In 1750, the center of the circle was fixed at the cupola
Cupola
In architecture, a cupola is a small, most-often dome-like, structure on top of a building. Often used to provide a lookout or to admit light and air, it usually crowns a larger roof or dome....
of the courthouse
New Castle County Court House
New Castle Court House Museum, also known as New Castle Courthouse Museum, is the center of a circle with a 12-mile radius that defines most of the border of the states of Delaware and Pennsylvania and a small part of the border of Delaware and Maryland...
in New Castle (however, subsequent changes have also been based on a different center point, several thousand feet to the northwest of the courthouse). The Twelve-Mile Circle continues into the Delaware River
Delaware River
The Delaware River is a major river on the Atlantic coast of the United States.A Dutch expedition led by Henry Hudson in 1609 first mapped the river. The river was christened the South River in the New Netherland colony that followed, in contrast to the North River, as the Hudson River was then...
. A small portion of the circle, known as the "Arc Line," also forms part of the Mason-Dixon line
Mason-Dixon line
The Mason–Dixon Line was surveyed between 1763 and 1767 by Charles Mason and Jeremiah Dixon in the resolution of a border dispute between British colonies in Colonial America. It forms a demarcation line among four U.S. states, forming part of the borders of Pennsylvania, Maryland, Delaware, and...
, separating Delaware and Maryland
Maryland
Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...
. And two other small portions, although not actually demarcated until 1934, form parts of the boundary between the states of Delaware
Delaware
Delaware is a U.S. state located on the Atlantic Coast in the Mid-Atlantic region of the United States. It is bordered to the south and west by Maryland, and to the north by Pennsylvania...
and New Jersey
New Jersey
New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...
. Although the Twelve-Mile Circle is often claimed to be the only territorial boundary in the United States that is a true arc
Arc (geometry)
In geometry, an arc is a closed segment of a differentiable curve in the two-dimensional plane; for example, a circular arc is a segment of the circumference of a circle...
(excepting those following arcs of latitude and longitude), the Mexican boundary with Texas includes several arcs, and many cities in the South (such as Plains, Georgia
Plains, Georgia
Plains is a city in Sumter County, Georgia, United States. The population was 776 at the 2010 census. It is part of the Americus Micropolitan Statistical Area.-Notable people:...
) also have circular boundaries.
Its existence dates from a deed to William Penn
William Penn
William Penn was an English real estate entrepreneur, philosopher, and founder of the Province of Pennsylvania, the English North American colony and the future Commonwealth of Pennsylvania. He was an early champion of democracy and religious freedom, notable for his good relations and successful...
from the Duke of York
James II of England
James II & VII was King of England and King of Ireland as James II and King of Scotland as James VII, from 6 February 1685. He was the last Catholic monarch to reign over the Kingdoms of England, Scotland, and Ireland...
on August 24, 1682, which granted Penn:
The fact that the circle extends into the Delaware River makes for an unusual territorial possession. Most territorial boundaries that follow watercourses split the water course between the two territories by one of two methods, either by the median line of the watercourse (the Grotian Method, after Hugo Grotius
Hugo Grotius
Hugo Grotius , also known as Huig de Groot, Hugo Grocio or Hugo de Groot, was a jurist in the Dutch Republic. With Francisco de Vitoria and Alberico Gentili he laid the foundations for international law, based on natural law...
) or, more often, the center of the main flow channel, or thalweg
Thalweg
Thalweg in geography and fluvial geomorphology signifies the deepest continuous inline within a valley or watercourse system.-Hydrology:In hydrological and fluvial landforms, the thalweg is a line drawn to join the lowest points along the entire length of a stream bed or valley in its downward...
. However, due to the text of the deed, within the Twelve-Mile Circle, all the Delaware River to the low-tide mark on the east (New Jersey
New Jersey
New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...
) side is territory of the state of Delaware.
New Jersey has often disputed this claim, as the rest of its territorial boundaries along the Delaware River are determined by the midline and thalweg methods. The dispute has been brought to the Supreme Court of the United States
Supreme Court of the United States
The Supreme Court of the United States is the highest court in the United States. It has ultimate appellate jurisdiction over all state and federal courts, and original jurisdiction over a small range of cases...
on three occasions (all titled New Jersey v. Delaware
New Jersey v. Delaware
New Jersey v. Delaware, 552 U.S. 597 , is a United States Supreme Court case in which New Jersey sued Delaware, invoking the Supreme Court's original jurisdiction under , following Delaware's denial of oil company BP's petition to build a liquefied natural gas pipeline and loading facility on the...
), most notably in 1934, and also in 1935 and 2007. The court's opinion for the first case contains an extensive history of the claims to this territory, and the second memorably enjoins New Jersey and Delaware from ever disputing their jurisdictions again.
Regardless of the Supreme Court's admonition to the two states against further litigation on this subject, they were back before the court as late as November 2005, when New Jersey's desire to approve plans by BP
BP
BP p.l.c. is a global oil and gas company headquartered in London, United Kingdom. It is the third-largest energy company and fourth-largest company in the world measured by revenues and one of the six oil and gas "supermajors"...
to build a liquefied natural gas terminal along the New Jersey shore of the Delaware River fell afoul of Delaware's Coastal Zone Act.
The court on January 23, 2006, appointed a special master
Special master
In law, a special master is an authority appointed by a judge to make sure that judicial orders are actually followed.In England, at common law, there were "Masters in Chancery," who acted in aid of the Equity Courts. There were also "Masters in Lunacy," who conducted inquiries of the same nature...
to study the border dispute, and on March 21, 2008, it upheld his report, which largely supported Delaware's authority.
Meanwhile the Delaware House of Representatives
Delaware House of Representatives
The Delaware House of Representatives is the lower house of the Delaware General Assembly; the state legislature of the U.S. State of Delaware. It is composed of 41 Representatives from an equal amount of constituencies, each of whom is elected to a two year term. The Delaware General Assembly...
considered a (symbolic) bill to call out the National Guard
United States National Guard
The National Guard of the United States is a reserve military force composed of state National Guard militia members or units under federally recognized active or inactive armed force service for the United States. Militia members are citizen soldiers, meaning they work part time for the National...
to safeguard the State's interests, while New Jersey legislators made comments about the battleship New Jersey
USS New Jersey (BB-62)
USS New Jersey , is an , and was the second ship of the United States Navy to be named in honor of the U.S. state of New Jersey. New Jersey earned more battle stars for combat actions than the other three completed Iowa-class battleships, and is the only U.S...
, moored upriver from the site.
Surveying the Circle
There is a persistent rumor that David RittenhouseDavid Rittenhouse
David Rittenhouse was a renowned American astronomer, inventor, clockmaker, mathematician, surveyor, scientific instrument craftsman and public official...
, the famous astronomer and instrument-maker of Pennsylvania, surveyed the circle around New Castle, but this is likely not correct. The circle was first laid out by surveyors named Taylor and Pierson in 1701. The 1813 "Memoirs of the life of David Rittenhouse" by William Barton surmises that Rittenhouse was involved in such a survey in 1763, based on a letter in which Rittenhouse mentions being paid "for my attendance at New Castle," but there is no clear record of what, exactly, Rittenhouse was paid for. His biographer, Brooke Hindle, guesses that Rittenhouse assisted with latitude or longitude calculations.
See also
- The WedgeThe Wedge (border)The Wedge is a small tract of land along the borders of Delaware, Maryland and Pennsylvania. Ownership of the land was disputed until 1921; it is now recognized as part of Delaware. The tract was created primarily due to the shortcomings of contemporary surveying techniques...
- Transpeninsular LineTranspeninsular LineThe Transpeninsular Line is a surveyed line, the eastern half of which forms the north-south border between Delaware and Maryland...
- Killcohook National Wildlife RefugeKillcohook National Wildlife RefugeKillcohook National Wildlife Refuge was a National Wildlife Refuge located on the east bank of the Delaware River adjacent to the current Supawna Meadows National Wildlife Refuge. It had originally been established in 1934 as a secondary sludge disposal site for use by the Army Corps of Engineers...
- Mason-Dixon lineMason-Dixon lineThe Mason–Dixon Line was surveyed between 1763 and 1767 by Charles Mason and Jeremiah Dixon in the resolution of a border dispute between British colonies in Colonial America. It forms a demarcation line among four U.S. states, forming part of the borders of Pennsylvania, Maryland, Delaware, and...