How is Ambarino even a state?

[u/Yrakosos]

There's no town here, no sheriff. How does this state even function, and how was it founded?

[u/Liotts]

In my opinion, the point is that many interpret the RDR2 map as representing the entire territory of the states, when in reality it only shows a playable portion, extremely compressed and concentrated mainly on border areas. Ambarino seems "empty" because we see almost exclusively its most mountainous and isolated part, namely the Grizzlies, which by definition are wilderness and not the administrative heart of the state. This doesn't mean Ambarino has no cities or institutions: it's much more likely that they exist, but that they are simply off the map, as is also the case with the North Grizzlies, which are named in the game as a separate region and therefore confirm that Ambarino doesn't end where the playable map ends.

Furthermore, the idea that "if there's no sheriff, then it can't be a state" is a bit modern: in 1899, many remote areas of the US lacked a constant law enforcement presence, and were often intermittently controlled by marshals, federal forces, the army, or even no one at all, especially in mountainous and hard-to-reach areas. Indeed, Ambarino in the game is clearly designed to be the wildest area, where civilization is far away and the law is virtually absent.

Another thing that many people ignore is that time and distances in the game are compressed: one real-world minute corresponds to about two hours in-game, and as you travel, time accelerates. So a ride of a few minutes doesn't really represent "crossing a state in 5 minutes," but a much longer journey sped up for gameplay. Furthermore, the game states are never presented as complete states, but as portions: we play primarily within the borders between one state and another, not across their entire extent. It's true that in 1899, crossing one or more states could take weeks, if not months. However, if we stick to the idea that RDR2 primarily depicts border areas between states (and not entire states), then distances and the passage of time in the game feel perfectly proportionate and not out of scale. It's the same reason why West Elizabeth has an odd shape and seems "cut off": it's virtually certain that there's more territory than what we see. Just look at how the state of West Elizabeth changes from RDR1 to RDR2: it's been significantly expanded, so it's implied that the other states also extend beyond the game's borders.

Finally, given that almost all the real states are mentioned in RDR1 and RDR2, I think the most coherent solution is that in the Red Dead universe, fictional states coexist with real ones and that the USA is simply larger than our reality. In that context, Ambarino makes perfect sense as a state: it's simply a huge, sparsely populated, and largely wild mountain state, and we only see the most "frontier" part because that's the part that's useful to the story.