USGS Gage Station CFS at Arvada.
From the W-192 Bridge at Sussex, the Powder River wanders along to the northeast and after about two hours you begin heading north. Here the river passes through a extremely arid region. The eroded hills are barren and support only a meager amount of vegetation. Even so this is a beautiful trip. There are frequent views of the snow covered Big Horn Mountains, willow thickets on wide shoals of mud, cut banks from two to ten feet high, a woodlot on every bend, and numerous snags and logjams of weathered cottonwood trees.
There are few hazards to watch for - an infrequent fence or two and an occasional section of carbody riprap - but no diversion dams. In the faster water near the apex of a bend there can be some large rocks, but these are easily avoided. As with most rivers in Wyoming, the main obstacle to deal with is the wind.
About nine hours from Sussex, you pass by the site of Fort Reno (on top of a bench on the west side) and a bit further is the Screeter footbridge. Below here, the river continues north through the Powder River Breaks. After about six hours you come to a county bridge at Malapai/Irigaray (just over half way to I-90).
Six hours further north, the river makes a sharp bend and makes a six inch drop over a small rock formation. Here Pumpkin Creek comes in from the east. After three more hours, you swing east away from Coal Butte and follow along a steep uplift on the right for about 300 yards. The river then turns along the base of a sandstone cliff and three hours downstream is another county bridge. Three hours further is the Powder River rest stop on I-90.