Twelve Mile Circle of Delaware

[roadman65]

I was reading why the state line between Pennsylvania and Delaware is in the shape of an arc.  It has to do with a circle being drawn that radiates twelve miles away from the courthouse in New Castle, DE.  So, basically all points on the DE- PA border are exactly 12 miles from this courthouse.


What I do not understand is what that has to do with the boundary of NJ being at the high water mark of the Delaware River instead of in the middle of the waterway like most river boundaries have.  In fact 12 miles downstream ( this is the only part that makes sense) the border of the Garden State and Diamond State does move to the middle of the Delaware River.  Then why is not part of MD in Delaware as the border is a straight line where the circle should be also?

[realjd]

I was reading why the state line between Pennsylvania and Delaware is in the shape of an arc.  It has to do with a circle being drawn that radiates twelve miles away from the courthouse in New Castle, DE.  So, basically all points on the DE- PA border are exactly 12 miles from this courthouse.


What I do not understand is what that has to do with the boundary of NJ being at the high water mark of the Delaware River instead of in the middle of the waterway like most river boundaries have.  In fact 12 miles downstream ( this is the only part that makes sense) the border of the Garden State and Diamond State does move to the middle of the Delaware River.  Then why is not part of MD in Delaware as the border is a straight line where the circle should be also?

Have you read the Wikipedia article? It's because the original treaty defined it that way for any points within the 12 mile circle. And the MD border does have a small arc segment.

[Brandon]

Read How the States Got Their Shapes.  It covers the 12 Mile Circle better than Wiki ever could.

[roadman65]

I was reading why the state line between Pennsylvania and Delaware is in the shape of an arc.  It has to do with a circle being drawn that radiates twelve miles away from the courthouse in New Castle, DE.  So, basically all points on the DE- PA border are exactly 12 miles from this courthouse.


What I do not understand is what that has to do with the boundary of NJ being at the high water mark of the Delaware River instead of in the middle of the waterway like most river boundaries have.  In fact 12 miles downstream ( this is the only part that makes sense) the border of the Garden State and Diamond State does move to the middle of the Delaware River.  Then why is not part of MD in Delaware as the border is a straight line where the circle should be also?

Have you read the Wikipedia article? It's because the original treaty defined it that way for any points within the 12 mile circle. And the MD border does have a small arc segment.

Yeah, I read it, but then again part of Salem County, NJ would then be in it.  Why go as far as the shore goes?

[Brandon]

I was reading why the state line between Pennsylvania and Delaware is in the shape of an arc.  It has to do with a circle being drawn that radiates twelve miles away from the courthouse in New Castle, DE.  So, basically all points on the DE- PA border are exactly 12 miles from this courthouse.


What I do not understand is what that has to do with the boundary of NJ being at the high water mark of the Delaware River instead of in the middle of the waterway like most river boundaries have.  In fact 12 miles downstream ( this is the only part that makes sense) the border of the Garden State and Diamond State does move to the middle of the Delaware River.  Then why is not part of MD in Delaware as the border is a straight line where the circle should be also?

Have you read the Wikipedia article? It's because the original treaty defined it that way for any points within the 12 mile circle. And the MD border does have a small arc segment.

Yeah, I read it, but then again part of Salem County, NJ would then be in it.  Why go as far as the shore goes?

It has to do with royal grants.  New Jersey (West Jersey) was a different grant, and the Twelve Mile Circle only went up to the water.  Maryland was a different grant, but Pennsylvania and Delaware were related.  The circle was to divide Delaware from Pennsylvania, but there was a piece of land out of any territory, and it overlapped with Maryland, across the Mason-Dixon Line (which is actually two lines, one N-S between DE and MD and one E-W between PA and MD).

[realjd]

I was reading why the state line between Pennsylvania and Delaware is in the shape of an arc.  It has to do with a circle being drawn that radiates twelve miles away from the courthouse in New Castle, DE.  So, basically all points on the DE- PA border are exactly 12 miles from this courthouse.


What I do not understand is what that has to do with the boundary of NJ being at the high water mark of the Delaware River instead of in the middle of the waterway like most river boundaries have.  In fact 12 miles downstream ( this is the only part that makes sense) the border of the Garden State and Diamond State does move to the middle of the Delaware River.  Then why is not part of MD in Delaware as the border is a straight line where the circle should be also?

Have you read the Wikipedia article? It's because the original treaty defined it that way for any points within the 12 mile circle. And the MD border does have a small arc segment.

Yeah, I read it, but then again part of Salem County, NJ would then be in it.  Why go as far as the shore goes?

Because the original treaty explicitly granted Delaware the river itself within that 12 mile circle.

[cpzilliacus]

What I do not understand is what that has to do with the boundary of NJ being at the high water mark of the Delaware River instead of in the middle of the waterway like most river boundaries have.  In fact 12 miles downstream ( this is the only part that makes sense) the border of the Garden State and Diamond State does move to the middle of the Delaware River. 

realjd is correct.  It has to do with grants from the [British] Crown.

Similarly, the entire Potomac River belongs to Maryland (and D.C.), up to the high water mark on the Virginia (and later, West Virginia) shoreline (with a few exceptions in the tidal Potomac River, where certain bays are in Virginia).

[hbelkins]

Similarly, the entire Potomac River belongs to Maryland (and D.C.), up to the high water mark on the Virginia (and later, West Virginia) shoreline (with a few exceptions in the tidal Potomac River, where certain bays are in Virginia).

However, West Virginia and Kentucky have up to the LOW water mark of the Ohio River; in Kentucky's case, as it existed in 1792 when Kentucky became a state. That was Virginia's boundary prior to 1792. Wonder why the Potomac's designator is the high water mark, while on the Ohio it's the low water mark?

[roadman65]

You know in DC's case, there is also land on the VA side of the Potomac that is not Virginia. In fact the NB Lanes of the GW Memorial Parkway are in Washington where it passes under the Memorial Bridge.  No part of that bridge is in Virginia and the circle on the opposite shore from the Lincoln Memorial is still in DC as well.

[cpzilliacus]

You know in DC's case, there is also land on the VA side of the Potomac that is not Virginia. In fact the NB Lanes of the GW Memorial Parkway are in Washington where it passes under the Memorial Bridge.  No part of that bridge is in Virginia and the circle on the opposite shore from the Lincoln Memorial is still in DC as well.

You spoke of Columbia Island, entirely in the District of Columbia, and entirely owned by the National Park Service (it is administered as part of the George Washington Memorial Parkway). 

The border between D.C. and Arlington County, Virginia runs on the "far" (or west) side of the island, on the high-water mark side of something called the Boundary Channel (there's a street that runs on the "river" side of the Pentagon in Arlington County called Boundary Channel Drive).

The southern end of the Boundary Channel has a marina (on Columbia Island), called, appropriately enough, Columbia Island Marina, which is entirely in D.C.  Boats there can reach the "main" Potomac River by passing under the George Washington Memorial Parkway's Humpback Bridge, which was recently reconstructed.   

The southbound lanes of the George Washington Parkway also enter D.C. briefly, where they cross over the Boundary Channel and under Washington Boulevard (Va. 27 to the west and south  of the Boundary Channel), and stay in D.C. until they cross back into Virginia at the Humpback Bridge, which is just north of I-395.

[Road Hog]

Another interesting border quirk: The Red River between Oklahoma and Texas belongs entirely to Oklahoma. The border is on the Texas side where the vegetation ends. An exception was made for Lake Texoma where the border follows the old river channel.

http://digital.library.okstate.edu/encyclopedia/entries/R/RE008.html

So to fish the Red River from the Texas side, you need an Oklahoma fishing license except for a designated area below Denison Dam where a Texas license is permitted. Both states sell a special Texoma license for the lake.