The trail left the main Oregon Trail at Fort Laramie and initially followed a familiar route northwestward before cutting away from established roads and into the Powder River Country.

The terrain north of the Platte River breaks into a series of distinctive geographic features — the rolling breaks above the Powder River, the flat-topped tablelands interspersed with deeply cut ravines, the increasingly dramatic country as the Big Horn Mountains come into view.

The trail had to cross several significant rivers: the Powder itself, the Tongue, and eventually the Big Horn.

These crossings were not trivially easy — the rivers ran high and fast during spring snowmelt, could be treacherous in summer flash floods, and froze to varying depths in winter.