# Straight-lined international and interior borders **URL:** \ **Category:** Factual Questions\ **Created:** [January 2, 2025, 3:43pm UTC](https://boards.straightdope.com/t/straight-lined-international-and-interior-borders/1012484 "2025-01-02T15:43:50Z")\ **Posts on this page:** 12\ **Page:** 6
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [December 28, 2025, 4:45pm UTC](https://boards.straightdope.com/t/straight-lined-international-and-interior-borders/1012484/101 "2025-12-28T16:45:23Z")
> [@TokyoBayer](#): > > That’s a myth. The divide was following the Bitterroot Range and was established by act of Congress. That’s why I said “supposedly”. But I don’t think that even Congress has the power to establish where the Continental Divide is 😉 ---
**Author:** ![Ancient\_Nerd](https://avatars.discourse-cdn.com/v4/letter/a/ed655f/32.png) [@Ancient\_Nerd](https://boards.straightdope.com/u/Ancient_Nerd)\ **Post date:** [December 28, 2025, 8:42pm UTC](https://boards.straightdope.com/t/straight-lined-international-and-interior-borders/1012484/102 "2025-12-28T20:42:43Z")
> [@Chronos](#): > > That’s why I said “supposedly”. But I don’t think that even Congress has the power to establish where the Continental Divide is Reality does not always stop politicians when it tries to get in the way. ---
**Author:** ![KCB615](https://avatars.discourse-cdn.com/v4/letter/k/ea666f/32.png) [@KCB615](https://boards.straightdope.com/u/KCB615)\ **Post date:** [December 28, 2025, 10:02pm UTC](https://boards.straightdope.com/t/straight-lined-international-and-interior-borders/1012484/103 "2025-12-28T22:02:13Z")
> [@dtilque](#): > > Just occured to me: The border between Massachusetts and New Hampshire is in part set as a displacement from a river. In this case it was 3 miles and I can’t remember the name of the river off-hand. But like the Senegal-Gambia case, there is probably some circular sections where the river makes a turn. The Merrimack River. There are definitely curves to the border, too. The border becomes a straight(ish) line heading west(ish) from the point three miles south of the southern most point of the Merrimack. The odd squiggle between New Hampshire and Massachusetts is the 3-mile offset. The same thing happens with the Charles River on the south border of Massachusetts (Rhode Island and Connecticut), only there isn’t a squiggly part. The border is a line of latitude offset from what was understood to be the southern most point of the Charles River. The Charles is more famous for being the river that empties into Boston Harbor, but it starts well inland and meanders as a narrow stream through eastern Massachusetts. ---
**Author:** ![TokyoBayer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tokyobayer/32/13989_2.png) [@TokyoBayer](https://boards.straightdope.com/u/TokyoBayer)\ **Post date:** [December 28, 2025, 10:09pm UTC](https://boards.straightdope.com/t/straight-lined-international-and-interior-borders/1012484/104 "2025-12-28T22:09:06Z")
The comment makes no sense because the boundary was the Bitterroot Range and not the Continental Divide. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [December 28, 2025, 10:12pm UTC](https://boards.straightdope.com/t/straight-lined-international-and-interior-borders/1012484/105 "2025-12-28T22:12:07Z")
It is true that the divide was, at least partially, following the Bitteroot Range. It’s true that the border also follows the range. But it’s not true that the Divide was established by act of Congress. ---
**Author:** ![TokyoBayer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tokyobayer/32/13989_2.png) [@TokyoBayer](https://boards.straightdope.com/u/TokyoBayer)\ **Post date:** [December 28, 2025, 10:20pm UTC](https://boards.straightdope.com/t/straight-lined-international-and-interior-borders/1012484/106 "2025-12-28T22:20:31Z")
> [@Ancient\_Nerd](#): > > Reality does not always stop politicians when it tries to get in the way. They didn’t attempt to. This was a myth repeated here by someone who failed to do a simple fact check. ---
**Author:** ![TokyoBayer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tokyobayer/32/13989_2.png) [@TokyoBayer](https://boards.straightdope.com/u/TokyoBayer)\ **Post date:** [December 28, 2025, 10:35pm UTC](https://boards.straightdope.com/t/straight-lined-international-and-interior-borders/1012484/107 "2025-12-28T22:35:19Z")
> [@Chronos](#): > > But it’s not true that the Divide was established by act of Congress. And no one said they did. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [December 28, 2025, 10:53pm UTC](https://boards.straightdope.com/t/straight-lined-international-and-interior-borders/1012484/108 "2025-12-28T22:53:01Z")
> [@TokyoBayer](#): > > And no one said they did. I mean, yeah, I get that that’s not what you meant, but what you said was > [@TokyoBayer](#): > > The divide was following the Bitterroot Range and was established by act of Congress. ---
**Author:** ![Toxgoddess](https://avatars.discourse-cdn.com/v4/letter/t/f08c70/32.png) [@Toxgoddess](https://boards.straightdope.com/u/Toxgoddess)\ **Post date:** [January 1, 2026, 7:20pm UTC](https://boards.straightdope.com/t/straight-lined-international-and-interior-borders/1012484/109 "2026-01-01T19:20:49Z")
[quote=“Crafter\_Man, post:83, topic:1012484”] [Some states came very close to war over border disputes]( [Toledo War - Wikipedia](https://en.wikipedia.org/wiki/Toledo_War) ). Michigan got the last laughs, with getting the UP and all [/quote] As a native Detroiter, I have on more than one occasion amused myself by asking non-Michiganders \* if they have heard of the Toledo War. And if they look confused, I add “Wisconsin lost.” \*\* Ohioans know what I am talking about. Nobody else usually does. \* It was “Michiganders” when I was a kid so it is always Michiganders, dammit. \*\* Ohio got the Toledo strip, and Michigan annexed the UP from Wisconsin. WI was just a hapless bystander. Foe this reason, if you look closely, the southern MI border is not straight. It makes a dogleg north around the aforementioned Toledo strip. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [January 1, 2026, 7:24pm UTC](https://boards.straightdope.com/t/straight-lined-international-and-interior-borders/1012484/110 "2026-01-01T19:24:20Z")
> [@Toxgoddess](#): > > As a native Detroiter, I have on more than one occasion amused myself by asking non-Michiganders \* if they have heard of the Toledo War. And if they look confused, I add “Wisconsin lost.” \*\* If you want to be snarky about the UP, you could say Wisconsin won. ---
**Author:** ![Toxgoddess](https://avatars.discourse-cdn.com/v4/letter/t/f08c70/32.png) [@Toxgoddess](https://boards.straightdope.com/u/Toxgoddess)\ **Post date:** [January 1, 2026, 7:25pm UTC](https://boards.straightdope.com/t/straight-lined-international-and-interior-borders/1012484/111 "2026-01-01T19:25:28Z")
Ha! True. They do call us trolls, after all (we live below the bridge) so a little snark is not uncalled for. ---
**Author:** ![Jaguars](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jaguars/32/5879_2.png) [@Jaguars](https://boards.straightdope.com/u/Jaguars)\ **Post date:** [January 14, 2026, 11:31pm UTC](https://boards.straightdope.com/t/straight-lined-international-and-interior-borders/1012484/112 "2026-01-14T23:31:48Z")
I don’t think that anyone answered this but I would be extremely surprised if the various borders within and around the US haven’t been resurveyed many times, not to shift their physical location but to better record where they are. It’s unlikely that any borders will be shifted due to better survey fix any time soon since as far as I’m aware none of the remaining territorial disputes focus on this issue. When these borders were marked out, both parties had to accept the results on the ground as acceptable (or dispute it). So while the common description of the boundary might be the 49th parallel, it’s more likely that the _real_ description will be something along the lines of ‘the 49th Parallel, as measured by Y’s resurvey of the positions monumented by X’s original survey.’ After all, it’s never possible to get it spot on. You can always get out your micrometer or electron microscope and claim the line deviates. Since there’s no global surveyor-general defining tolerances and regulations for this sort of thing, the parties have to agree by treaty. Once the marked line is acceptable a much more precise record will likely be made of it than the principles that originally guided the definition. [Previous page](https://boards.straightdope.com/t/straight-lined-international-and-interior-borders/1012484.md?page=5)