DelaWhere?

Delaware's Boundaries

Conflicting claims of ownership between Maryland and Delaware kept Delaware's boundaries uncertain during most of the colonial period and led to highly geometric dividing lines on the north, south, and west. 

 

North

Northern Boundary: The Twelve-Mile Circle

The northern boundary marks the division between the two separate land grants to William Penn.  It is a circle with a twelve-mile radius, with the center of the circle in the center of the town of New Castle. In 1750, the center of the circle was fixed at the coupola of the courthouse in New Castle.

 

South

Southern Boundary: The  Transpeninsular Line

In 1751, a line was surveyed straight across the Delmarva Peninsula beginning at what they called Cape Henelopen, which was to be the  southern boundary of Delaware.  The surveyors, however, actually began at Fenwick Island, fifteen miles south of what is today Cape Henelopen.

 

West

Western Boundary: Survey by Mason & Dixon

In 1760, the midpoint of the tranpeninsular line was accepted as the beginning of Delaware's western boundary with Maryland.  In 1764, Charles Mason and Jeremiah Dixon surveyed the boundary line north from that point.  Mason and Dixon also verified the transpeninsular line.

 

The
Wedge

The Wedge: A tiny piece of land in northwestern Delaware bordering on Maryland and Pennsylvania.

When Mason & Dixon surveyed the western boundary of Delaware the line they ran northward from the midpoint of the transpeninsular line did not quite meet the twelve-mile circle.  It ended up a little to the west.  Ownership of this land was in dispute until 1921, when it was granted to Delaware.

 

East

Eastern Boundary: The Delaware River & Bay

The twelve-mile circle continues into the Delaware River. Below it, the center of the main ship channel in the Delaware River and Bay is considered to be the boundary with New Jersey.

 

The
Mason
Dixon
Line

The Mason Dixon Line: Is Delaware North or South of the "Mason-Dixon Line"?

For the most part, Delaware is east of that famous line that traditionally divides the North from the South.  Mason and Dixon surveyed the Pennsylvania-Maryland boundary westward from a point on the twelve-mile circle.  Only the small portion of the Mason-Dixon Line that is the top of the wedge is part of Delaware's boundaries.