Rather famously, the western United States have rather arbitrary borders, boxy figures defined by parallels and meridians, which has had the rather hideous consequence of placing e.g. very different regions separated by 14,000-foot tall mountains in the same state (Colorado, I’m looking at you). More importantly, it has made water management a nightmare, an issue which was famously identified by John Wesley Powell as early as the 1870s, who championed demarcating borders not by arbitrary lines on a map but rather by the natural boundaries of watersheds, a cause which found support by experts even decades earlier. We didn’t have to have such Frankenstein-monster-esque states out west! But true to form, Congress tossed these suggestions into the garbage can, to the detriment of us all.
For context, here’s a rather excellent watershed map of the United States, Canada, and Mexico, covering the vast majority of North America:
There are various basins that could be used as boundaries, which is more a matter of judgment, but let’s say we’re working from a blank slate, as America nearly was in the 1840s! The two really important boundaries, which would form cross-country borders in any “watershed-based boundary plan for the west”, are the 100th meridian, the famous (rough) dividing line between humid and arid climate (and also between farming and ranching country), and the Continental Divide. On the map below they appear to the right and to the left, respectively.
Notice, that aside from sections of the Idaho-Montana and Oklahoma-Texas borders, the above doesn’t correspond to any current boundaries. Anyway, we don’t want there to be just two huge states, one east of the divide and one west, so how to subdivide this territory further? I think the next-most-obvious boundaries would be the Colorado River watershed and the Great Basin. Notice that we now essentially have a super-Arizona and a super-Nevada.
These states are somewhat too big, at least if states near our timeline’s counterparts in area are desired, so further subdivision will be necessary. The obvious division for the Colorado watershed would be Glen Canyon, our Lake Powell, which yields two similar-sized compact chunks. There are quite a few ways to divide the Great Basin, but it makes sense for the Great Salt Lake watershed to form its own state, as it’s sorta its own entity, and integrating the Sevier Lake watershed with it would make eminent sense even if its population didn’t share the unique Mormon faith. I was tempted to divide what remains of super-Nevada into a northern and southern segment, but unlike the Great Salt Lake the dividing line isn’t really obvious, and the region is so sparsely populated anyway it might be thought of as being better off unified.
Now we move onto the segment that drains out to the open Pacific. The Cascadia bioregion in most maps (i.e. the Pacific Northwest) is extended southward through the Klamath River watershed, which lops off yet another piece of California, this time the northernmost segment. Interestingly, in real life this region has been a hotbed of secessionist sentiment, seeking to join with southern Oregon and establish a State of Jefferson, so tying this area together with Cascadia would seem to be more natural than California. Northward of the Klamath the Cascade Range rises, and the obvious division would be along its crest.
Frankly, if you ask me it’s bizarre that the Oregon Territory wasn’t divided this way in real life; if it needed to be cut into two pieces, wouldn’t an east-inland and west-coastal piece be far more coherent than a north piece and south piece that each blended both regions? Anyway, the part of the Columbia River watershed that remains east of the Cascade crest would form a sort of super-Idaho. This could be divided further, but it would make a perfectly nice and coherent state roughly the same size as our Montana (or this timeline’s super-Nevada), so why not just leave it? In my view if Idaho is to have the northern segment it has in real life it really ought to have been made substantially bigger anyway, so as to encompass adjoining regions with natural ties to the panhandle. Even now there’s a movement afoot to annex eastern Oregon and Washington to Idaho. Hmm.
Here’s the result of all these borders. West of the continental divide is now complete. We have 7 states west of the continental divide. Incidentally this is exactly the same number of states we have now that are wholly west of the continental divide: 7. Because the eastern boundary of our “states wholly west of the divide” averages a hundred miles or so west of the actual divide, these 7 states average modestly larger in area than ours.
East of the Great Divide lies (mostly) the High Plains, which lacks much in the way of blatantly obvious hydrographic boundary lines. New Mexico, however, was a thing for centuries prior to the 1840s, and the Rio Grande watershed is quite distinct and important, so I assign New Mexico the entirety of the Rio Grande watershed north of the Mexican border and west of the 100th meridian. Notice this roughly corresponds to the region where to this day Mexican-Americans have a longstanding and heavy presence, as contrasted to points northeastward.
Northward of the Edwards Plateau or so in what’s now West Texas, a nice coherent compact unit is formed by marking the northern border of this state at the Missouri River watershed. This state would be roughly the same size as our Idaho. Perhaps interestingly, this state includes Colorado Springs and Pueblo but excludes Denver.
The remaining state that mostly consists of Big Sky Country is a bit too big for comfort, so we’ll divide that further. The most obvious division here is the Platte River watershed, which makes a nice little state stretching from Denver to Casper and then eastward to the 100th meridian. The state northward of Casper that remains is still a bit too big, being larger than Montana, so I pulled a Colorado-basin type move on it and subdivided it into an upper and lower watershed portion. Upward of what’s now Lake Sakakawea is one state, roughly corresponding to our Montana, and then the remaining portion lower than that is another state, roughly corresponding to the western Dakotas.
So there we have it. 5 states lying wholly to the west of the 100th meridian but not wholly west of the continental divide. The count in real life is just 4. Like the states west of the divide, they’re modestly larger than their current-day counterparts because they must sprawl eastward; the farmer-dominated states of the Low Plains don’t take in arid ranching country in the American West like they do now. Below is the map of the new American West; if nothing else, isn’t it so much more aesthetically pleasing than the boxy states of today? 🙂
And here’s some names I picked out for these states.
California, Nevada, Arizona, Utah, and New Mexico were basically always known by those names. Colorado is named after the river. The part of Cascadia west of the crest is christened Tacoma, after the mountain (now better known as Mount Rainier), with the bigger piece of the Oregon territory keeping the name of Oregon. Alt-Montana is known as Absaroka, after the mountain range, which is located centrally in the new state. Cheyenne is named after the river and the nation. Arapaho is named after the first nation, whose range more or less overlaps the state. Cimarron is named after the river.
Pretty cool if you ask me. 😀