Jocko Hollow on the Jocko River near Arlee, Montana in the early 1900s (Edward S. Curtis V7-p232), and in 2014 (CW-2014-05-21-1860).
There are several locations along the Jocko River where this image could have been taken. Perhaps some judicious sleuth can exactly relocate it by finding one of the original trees. So far this has eluded me, but it is always a pleasant break from driving busy Highway 93. As often happens, what was once a classic streamside Indigenous camping ground on a well-drained, and routinely burned alluvial plain has disappeared due to irrigated wet soils and dense shrubby vegetation.
Map