[Hardcase]

In Idaho, prior to statehood in 1890, there were "Committees of Vigilance" in a few counties. One of them, in Payette County, was headed up by the future first governor of the state.

I don't know how things worked politically in other states between 1860 and 1890, but in Idaho, there tended to be more Southerners than Yankees in the mining towns and there was significant friction between them. Since Idaho became a territory during the Civil War, the appointed officials were all Northerners. But due to the significant Southern population of certain counties, elected officials tended to sympathize with the Confederate side.

What they ended up with was that the Sheriff and his deputies tended to not arrest those of their ilk and the judges tended to drop charges against their kind. Into the breach came the Committees of Vigilance.

That doesn't really answer the question of who owned horses. I know that the sheriffs in Idaho City tended to own them because the county is very large and they had to regularly travel between several towns. But my impression is that they had their own horses, not provided for by the county.

Incidentally, Idaho is littered with ghost towns (and living ones, too) that are named after places in the south. Atlanta and Dixie among others, and the Secesh (for "secession") river, as examples.