[ctdonath2]

Seems deeds are predicated on boundaries being immutable. When they change, they are retroactively adjusted changing the current boundaries and treated like nothing ever changed.

[greeneyes]

So you are saying that the river changes course and in the example, the increased land on the south belongs to the southern rancher, and the rancher to the north just loses some acreage?

That is my understanding of what is generally true, but I could see that there might have been some provision in the deed so that each Rancher would maintain the same acreage.

Point is what does it have to do with the Fed? The land belongs to the Ranchers be it the guy on the northern side or the guy on the southern side. Fedizilla has no claim to any land, if the deed references the red river as the boundary.