Delaware Boundary Monuments
Journey to Mark the First State's Boundaries
Delaware is located in the U.S. Mid-Atlantic region.
Delaware was the "First State" to ratify the U.S. Constitution but possibly is the last state to have its boundaries settled. It took from 1681 to 1934 to settle and mark most of them.
The state of Delaware's boundaries with Maryland, Pennsylvania, and New Jersey are marked with 179 monuments. Most of the original historical monuments are stone, and more recently placed monuments are metal disks.
They are jointly maintained by the State Of Delaware, Division of Parks and Recreation and Division of Historical and Cultural Affairs , since many are listed on the National Register.
Four major boundaries make up the confines of the state of Delaware:
- East-West
- North-South
- Delaware-Pennsylvania
- Delaware-New Jersey
Delaware is located in the northern portion of the Delmarva Peninsula.
The Delmarva Peninsula consists of Delaware and portions of Maryland and Virginia.
East-West Boundary
1750
During the 1600's, William Penn (founder of Pennsylvania) and George Calvert (founder of Maryland) were struggling for control of the Delmarva Peninsula region.
After decades of territory disputes, a bipartisan commission sent colonial surveyors to Fenwick Island on the Atlantic coast to mark a Transpeninsular Line west to the open water of the Chesapeake Bay.
The Colonial surveyors used a compass to determine the bearing of the survey line and a 66-foot chain to measure distance.
Marking this line was extremely hard work as this area was unsettled wild lands at this time. There were streams and creeks to cross and trees and brush to cut for sight lines. Unlike today, there were no chain saws or bulldozers, no roads or bridges, and no insect repellent.
1760
The commissioners accepted the 1750-51 survey and fixed the Middle Point of the Transpeninsular Line by marking it with an oak post. This location eventually became the southwest corner of Delaware.
A stone monument was set every five miles along the eastern portion of the Transpeninsular Line except at mile 15 because of the unsuitable conditions around the Pocomoke River and surrounding swamps.
The stones are metamorphic gneiss of unknown origin and bear the crest of the Calvert on one side and Penn on the opposite side.
Crest of Calvert (facing south) and Penn (facing north).
Transpeninsular Line monument 14.
1974
The Delaware and Maryland Boundary Commissions requested that the Transpeninsular Line be marked at one mile intervals between the five mile stones. The National Geodetic Survey (NGS) began this work in 1976 and placed a brass monument at each location.
In the U.S., the National Geodetic Survey provides the framework for all positioning activities in the Nation.
A pavilion was erected in 1961 by the Daughters of the American Revolution to protect four stone monuments at Middle Point (the southwest corner of Delaware).
Transpeninsular Line monument 35
Monument set by Colonial surveyors in 1760; originally set 32 inches north of an oak post marking the Middle Point.
Tangent Line monument 0
Monument set by Mason and Dixon in 1768 marking the true Middle Point.
Transpeninsular Line monument 25
During highway construction in the 1950's, monument 25 was reset 13.8 feet to the south because it was in the shoulder of the road.
It was damaged by automobiles and farm equipment, so it was moved to Middle Point in 1984 where it would be safe. A brass disk was placed beneath a manhole in its original location in the roadway.
Transpeninsular Line monument 25 at the original location.
Extra stone
A local farmer said his grandfather found the stone in his field and thought it resembled the stones in the pavilion so he placed it there. It has no official significance but remains in place.
Delaware's western boundary with Maryland is made up of three segments:
- Tangent Line
- Arc Line
- North Line
Tangent Line
1763
Charles Mason and Jeremiah Dixon were commissioned to lay out the boundaries between the colonies of Maryland and Pennsylvania.
They began at Middle Point surveying a line tangent to the Twelve-Mile Circle.
Twelve-Mile Circle, 1682
William Penn (founder of Pennsylvania) wanted secure access to the Atlantic Ocean. The Duke of York granted to Penn the town of New Castle and the tract of land in a circle with a twelve mile radius, the center of which was the courthouse in New Castle.
The Tangent Line was originally supposed to continue directly north from the Tangent Point to the northeast corner of Maryland.
Arc Line
After running the Tangent Line, Mason and Dixon discovered that the Tangent Point was not in the correct location, causing the North Line to pass through the Twelve-Mile Circle.
Mason and Dixon solved this problem by creating the Arc Line which follows the Twelve-Mile Circle from Tangent Point for 1.5 miles until it intersects with the North Line.
The extended area within the Arc Line contains about 13 acres and is part of Delaware.
Photo: Monuments at Tangent Point set by Mason and Dixon in 1765 (left) and Graham in 1849 (right).
North Line
The segment called North Line starts at the top of the Arc Line and continues north until it reaches the current Pennsylvania and Maryland border.
Stone monuments made of limestone were set at every mile point along the Tangent, Arc, and North lines. They were quarried in England, brought over by ship, and placed in late 1765.
Delaware, Maryland, and Pennsylvania are the only states in the U.S. that have boundaries marked with foreign stones.
North Line monument 25.
Monuments at every five miles have the coat of arms of Lord Calvert (west side) and the Penns (east side). These monuments are called Crownstones.
North Line monument 84.
Monuments at the other mile points have an "M" facing the Maryland side and a "P" facing the Delaware side.
In Colonial times, Delaware was considered the three lower counties of Pennsylvania.
The Wedge
Boundary activities settled until the 1840s when it was noticed that the monument at the northeast corner of Maryland had disappeared (blue point on map).
In 1849, the Commissioners from Delaware, Maryland, and Pennsylvania assigned Lieutenant Col. James D. Graham of the U.S. Army to lead a team to conduct a survey.
During his survey, Graham determined that the intersection of Delaware, Maryland, and Pennsylvania was located where the North and Arc Lines meet (yellow point on map).
Intersection stone where the North and Arc Lines meet.
By doing this, he changed the position of the original location (blue point) which caused the Twelve-Mile Circle to extend further south (yellow line on map).
Graham's change created a 714-acre triangular strip known as the Wedge that became part of Pennsylvania instead of Delaware.
For years this area became a hideout for thieves and petty criminals and a place for gambling, prize-fighting, and duels because of uncertainty over which state had jurisdiction of the Wedge.
This confusion was resolved in 1889 when the Wedge was reassigned to Delaware, but Delaware did not officially accept it until 1921.
The Delaware-Pennsylvania Boundary starts from the top of the North Line (orange solid line) and runs east until it intersects the Twelve-Mile Circle (yellow dashed line).
This line segment (blue line) is also known as Top of the Wedge Line.
The boundary then follows the arc of the Twelve-Mile Circle to the Delaware River.
The Twelve-Mile Circle boundary between Delaware and Pennsylvania is the only state boundary in the U.S. that is circular.
1701
William Penn appointed Isaac Taylor of Chester County and Thomas Piersons of New Castle County to survey the boundary between the counties (which later became the boundary between Delaware and Pennsylvania). The circular line was marked by blazed (ax cuts) trees.
1890s
Nearly two hundred years later, Delaware and Pennsylvania had no clear information as to the actual location of the boundary. Commissioners from both states obtained the services of Colonel W.C. Hodgkins of the U.S. Coast and Geodetic Survey to locate and mark the boundary.
Hodgkins Survey 1892
Although Hodgkins used triangulation to insure accuracy, he found only four points that had been marked by Taylor and Piersons (approximate locations on map):
- large hickory stump
- peculiar "S" curve in the Brandywine Creek
- northern boundaries of farms east of the Brandywine Creek
- remains of an old house
Hodgkins first determined where the Twelve-Mile Circle intersects with the Top of the Wedge Line. The monument at this location is called Arc Corner (yellow point on map).
Arc Corner monument, 1984.
In order to make the survey fit the four known points, Hodgkins was forced to survey two compound arcs. The first arc began at Arc Corner and ended at point 1 (large hickory stump).
The second arc began at point 1, passed through points 2, 3, 4, and ended at a location called Terminal Monument.
Terminal monument, 1984.
Fourty-four granitic gneiss monuments (quarried in Chester County, Pennsylvania) mark the boundary at half-mile intervals between Arc Corner and Terminal Monument.
Delaware-Pennsylvania Boundary monuments 4 (left) and 7 (right).
Monuments placed at every mile have a "D" on the side facing Delaware and a "P" on the side facing Pennsylvania.
Delaware-Pennsylvania Boundary monuments 5 (left) and 4 (right).
The side facing Arc Corner has a number which represents distance in miles from Arc Corner, and the fourth side has "1892" which is the year of the survey.
Delaware-Pennsylvania Boundary monument 10 ½.
Monuments placed every half-mile only have "½" marked on the side facing Arc Corner.
Delaware-New Jersey Boundary
Disputes over shad fishing in the Delaware River arose during the late 1800s between Delaware and New Jersey. The development of the oyster industry in 1929 further fueled disputes over the boundary in the river. Delaware attempted to claim all the river and land within the Twelve-Mile Circle.
A suit was entered in the U.S. Supreme Court between Delaware and New Jersey to settle the boundary between the states.
In 1934, the U.S. Supreme Court issued a decree stating that within the Twelve-Mile Circle, the Delaware River waterway and river bottom up to the 1934 Mean Low Water Line on the New Jersey side (red line) belongs to Delaware.
Six monuments mark this portion of the Delaware-New Jersey boundary. Five reference the 1934 mean low water line and one marks a portion of the Twelve-Mile Circle.
Delaware-New Jersey Boundary reference monument. Arrow points toward the 1934 Mean Low Water Line.
When the southern end of the line reaches the Twelve-Mile Circle, it follows the circular boundary west through monument 6 until it reaches the middle of the Delaware River.
The boundary crosses through Artificial Island, causing the northern tip to be in Delaware.
Delaware-New Jersey Boundary monument 6, Artificial Island.
Another location adjacent to New Jersey that is part of Delaware was historically known as the Killcohook Disposal Area (red star). Dredge spoils were placed on the land and out into the river and became solid ground.
Since it was located west of the established 1934 Mean Low Water Line, the area fell in Delaware.
President Franklin Roosevelt created the Killcohook Migratory Bird Refuge at this location in February 1934.
It later became Killcohook National Wildlife Refuge, but its status as a wildlife refuge was revoked in 1998 by U.S. Congress. It is currently being used as a confined disposal area by the U.S. Army Corps of Engineers.
Fun fact: This disposal area and the tip of Artificial Island are places where it is possible to drive from New Jersey to Delaware without crossing water.
South of the Twelve-Mile Circle, the Delaware-New Jersey Boundary follows the main shipping channel in the Delaware River and Bay. This line segment is called Delaware Bay Line.
Delaware Bay Line (green) that divides Delaware and New Jersey.
1981
Dr. Robert Jordan, Director of the Delaware Geological Survey and Chairman of the Delaware Boundary Commission, assigned William "Sandy" Schenck to lead a project to restore and protect Delaware's boundary monuments.
Sandy worked closely with Ralph Poust of the National Geodetic Survey and Roger Nathan, a retired New Jersey school principal and Mason-Dixon enthusiast. This was the first of many projects Sandy worked on during his 40-year career at the Delaware Geological Survey.
Roger Nathan (left) and Sandy Schenck (right) at Transpeninsular Line monument 14 , 1986.
If you are interested in locating any boundary monuments, please remember that most are located on private property. Always ask for permission to visit on someone's land.
Acknowlegement:
This Story Map contains excerpts from Roger Nathan's book "East of the Mason-Dixon Line: A History of the Delaware Boundaries".
References:
Nathan, R.E., 2000, East of the Mason-Dixon Line: A History of the Delaware Boundaries, 104 p.
Schenck, W.S., 1989, Delaware's State Boundaries, Delaware Geological Survey Information Series No. 6, 2 p.
