I read long ago about an island whose location helped delineate the boundary between Massachusetts and one of either Rhode Island, Connecticut, or New York (via Long Island) . There was an issue that the island was very low and sometimes disappeared for years at a time.
I became interested as to what would/will happen with rising sea levels when the island permanently disappears.
Can someone identify this island?
Searches bring up Billingsgate Island (or ‘Shoal’) which sounds a lot like it but can’t be the one - it’s lies within Cape Cod Bay.
In a weird coincidence I was reading about this issue as it pertains to the border between New Jersey and New York, and I think it could be what you’re thinking of too–this article on the U.S. Supreme Court case surrounding the issue explains it fairly well:
The TLDR is that a colonial land grant was worded weirdly, and it ends up Ellis Island is the location of a weird enclave of New York State, that is fully surrounded by territory of New Jersey.
How clear is your memory of this? It doesn’t look to me like Massachusetts borders on New York via Long Island. I’m not finding precise information on states maritime borders, but it looks like RI separates the two.
I did find something about an island having changed hands between Connecticut and NY, but although it weirdly doesn’t show up in map view in Google Maps except by name, it looks quite substantial in satellite view.
Wicopesset Island is the northernmost area of Suffolk County, New York, and previously the southernmost area of New London County, Connecticut. Fishers Island, New York - Wikipedia
Not finding any information on when and why it changed hands though.
I can’t say I’m 100% certain on all this but, the point is that the presence of the island would extend Massachusetts’ coastal zone further out into the ocean. Here’s a map;
Red Rock Island in San Francisco Bay has a point where San Francisco, Marin, and Contra Costa counties all come together. I’ve imagined it was so the surveyor had a place to drive in the marker.
Likewise, I figured that where the California and Nevada state lines dogleg in Lake Tahoe, there should be a buoy or something.
There are sandbars on the eastern shore of Cape Cod that look like candidates for the scenario you describe, haven’t been able to find anything on it though. Are you saying this island is disappearing but if it didn’t the MA coastline would extend further into the Atlantic? Any other hints about this?
Another possibility of a problem arises if an island in MA waters get larger and then becomes closer to Rhode Islands coastal limit. We wouldn’t look kindly on something like that here in RI. Probably just lead to another border dispute with MA. We haven’t had a big one for a while, mostly fighting over who plows the streets lately.
I can’t think of how land can dissappear for years at a time, and then come back.
But two people can argue if the swamp is wet by the river, or just wet by water flow from uphill of the swamp.
There is often a high (or low) water line defined, this ignores floods, freak king tides and storm surges, droughts and soon, so no need to think the border changed due to the water level being temporary.
What happens in Chesapeake Bay is that the land is DROPPING (due to settling of the continent after the ice age its faster than most other places ), which combines with rising sea levels and normal erosion , to make islands disappear permanently. But no the borders didnt change due to islands disappearing, the islands at the main borders are of solid (and tall) rock…
When the surveyor does a quick trip through, he might variously see a swamp as being land, or as being part of the river… and other issues to do with measuring latitude and assuming rivers dont go further north or south than the definition can handle… And so Rhode Island was in dispute with Mass for quite a while, due to the various interpretations and difficulties in accurately marking the border. The north border of Massachusetts was locked in place in 1897, with definitions independent of the rivers, thus solving the problem of the changing river edges and interpretations. See https://www.msp.umb.edu/placereadings2.html
