#26 on cover.
This goes with my last post.
Brownville, in the Nebraska Territory, is up the Missouri River a way from St Joseph. So this cover originated in one territory, traveled into the US (at St Joseph), then traveled into the Kansas Territory. At least the US considered it the KT. Some of the people there called it something else.
In looking at this cover, and the last one I posted, where oh where is Mountain City?
The Jefferson Territory was (illegally) formed by miners in the mountain area because they were so cut off from the rest of the world, that they felt that they needed their own representation.