It's theoretically possible under ideal conditions but probably not practical.

There is a maximum hop count of 7 which means there can be, at absolute maximum, seven nodes between the sender and recipient. The default, though, is 3 hops.

While the radios may, in theory, be able to work at the range of "a few states over" as the crow flies, terrain, structures, and line of sight would likely prohibit them from working in practice at such distances. You'd also need a reliable series of hops to reach from you to them. Again, at those distances, you'd very likely exceed the maximum hop count pretty quickly.

From what I've seen, large meshes are generally regional.

There's a way to join meshes over the internet via MQTT but I haven't messed with setting that up and in some cases it can potentially overwhelm a local mesh.