Look at an atlas of NJ. Look at the DE Bay and locate the DE-NJ border. Now, follow the border up the DE river - very carefully. If you are observant, you will see how the line doesn’t follow the river, but the border line turns due east cutting across a small peninsula of SW NJ. To help you locate it, it may help to know it’s about 15-20 miles south (as the crow flies) of the DE Memorial Bridge (i.e. the southern end of the NJ Turnpike). No towns are immediately near here, but you may see the names “Salem” or “Pennsville” to the W-NW.
The northern tip of this peninsula is actually a part of DE -east of the DE River! What’s the deal with that?
I don’t have any specific information on the boundary (although I have a general memory that prior to the War for Independence, Deleware had feuds with just about every one of its neighbors regarding its boundaries), however, I do note that the East-West line where the boundary cuts across the peninsula is just about exactly at latitude 39º 30’. This would suggest that it was simply a point picked for the line to shift east out of the water. From that point, it follows the water line, with Delaware getting all the water and New Jersey ending at the shore until the river bend northwest of Fort Mott, where Delaware gets a bit of the eastern shore, as well, following which the border reverts to the water line.
Apparantly it’s because it’s landfill. Apparantly they decided that DE owned the river down to just south of the Alloway River and then south of that the boundary would be in the middle of the Deleware River. Then they made new land over the older boundary which stayed the same.
Ny/NJ have the same thing where NY owns Liberty Island but all the newly created land around the island belongs to NJ. I’m right aren’t I? And let’s not get started with all the changes on the Mississippi River, although those are mostly natural.
Saw this on some local news. Delaware does own a piece of land that looks like it should belong to NJ. Although, I forget the reason it wound up that way.
Might sound strange, but my memory says it’s something about hunting game.
There are some references you can dig up about the Army Corps of Engineers using the Killcohook area as a dredge spoil disposal site, such as this blurb from 1998:
It looks to me as if it’s artificial, like that other area Osiris pointed out on his maps, and which was marked as such. The shore was the border, and the land got built out when the Corps started dredging and dumping muck off the bottom of the shipping channels there. They kept the border, and Delaware inherited the landfill.
What strikes me as strange in the first place is that Delaware originally got the whole river, rather than the border running down the middle of it.
Yeah, I thought I once saw that there were two places of this anamoly. (This has bugged me for some time, but I forgot about the second instance). Very strange…
By the way, very cool maps of good level of detail!
These situations are common with water boundaries. Take a close look at the states bordering the Mississippi River–especially toward the delta–and notice how often the boundary jukes onto dry land. Rivers change course, silt up, are dammed up, cut new channels, are cut off by landfills. Sometimes the boundary is defined as the center of the river, other times as the “low water mark” on one side or the other. Every combination of circumstances presents special problems and keeps lawyers busy.
I don’t have any specific information on the DE-NJ case, but it appears that the boundary follows the “low water mark” of the Delaware River on the NJ shore to about Salem Cove and then cuts to the middle of the channel. Most likely, after this boundary was surveyed and defined, land that had been under water within the river channel dried up, either through natural causes or landfill. The boundary remains in the same place, so the land is part of Delaware.
For “border buffs” who are interested in this sort of thing, I recommend a visit to Chamizal National Monument in El Paso, Texas. It tells the story of surveying and defining the Rio Grande border between the United States and Mexico, and the many problems caused when the river changes course, in fascinating detail.
That’s also true of the Potomac border between MD/DC and VA. The entire Potomac is in MD/DC and VA doesn’t get any of it. The border is on the right (VA) bank. But is it the high tide or the low tide line?
I know a technical term used by the people who draw (and litigate) boundaries. The “border running down the middle of it” is called the thalweg (German for ‘valley way’). Actually, the thalweg isn’t necessarily in the middle of the river; it’s supposed to be the deepest part of the riverbed. So that if the level of the river ever went down and the river shrank, what’s left of it would still be the boundary. Most riverine boundaries follow the thalweg, and I too wonder about the historical reason why one state (they were colonies when the boundary was drawn) gets to hog the whole river to themselves (you can tell I’m a Virginian, can’t you?).
Or at least as close as you can get to it. I grew up in South Jersey and love map anomalies, so in HS I drove out there with a freind and using local maps we tried to get close to it, but there were no roads that go within a mile of it, so there was no “welcome to Delaware” sign…
There’s a million of these things along the Mississippi. Anybody been to one?
If it’s any consolation, Jomo Mojo, Virginia grabbed the entire Ohio River when defining its boundaries in the West. This had profound consequences in American history. Aaron Burr hatched his conspiracy on Blennerhassett Island in the middle of the Ohio River, and it was only because the river belonged to Virginia that Burr’s trail took place before John Marshall in Richmond.
But this is probably no consolation to you today, because these areas are no longer part of Virginia, having long since broken off into KY and WV.
furt, most of those Mississippi River anomalies are about as tough to get to as the one you describe in New Jersey. They’re places where the Mississippi changed course, so they tend to be low-lying, frequently flooded sloughs and bayous without any roads. But again, if you find that sort of thing interesting, go to Chamizal! It was once a finger of Mexico jutting north of the Rio Grande River after the Rio Grande changed course. Mexico ceded it to the United States as part of a new boundary settlement in 1964.
This is how it happened… The upper end of Delaware was created by drawing an arc centered on the old courthouse in New Castle, and with a radius equal to the distance from the courhouse to the DE/MD border. That arc intersects land on the north side of the river mouth, but that land used to only be actually land during low tide. Since the Corps of Engineers have gotten involved, it may actually be high and (mostly) dry all the time now.
This arc also left a small triangle of land between MD, DE, and PA unincorporated in any state, and for a while was a small but quite lawless location. DE eventually annexed it, because MD and PA couldn’t be bothered. It’s still referred to as the “Triangle” today, though it doesn’t look like one anymore - It’s the squared-off projection just to the west of the begining of the arc.
Sorry, but the two bits of DE on the Jersey side of the border are not the result of the border arc. Take a look at a map and you’ll see that if the arc extended past the river, a much larger chunk of NJ would be part of DE.
BTW, in addition to the numerous Mississippi examples of this, there’s two on the Wabash River where bits of Indiana are on the Illinois side.
The biggest of those riverbank anomalies is that chunk of Kentucky that’s surrounded by Missouri. In 1811-1812 the most powerful earthquakes ever recorded in the United States struck, with the epicenter at New Madrid, Missouri. That made the Mississippi run backward for a while. Not surprisingly, the river wound up in some new channels afterwards. The old state border where the river used to be wasn’t changed.
The geophysics department at Saint Louis University has been monitoring seismic activity along the New Madrid Fault very carefully.