Upper Mountain Fork River is a seasonal stream that holds levels best during the late fall, winter and spring. It forms near Hatfield, Arkansas, southwest of Mena along US Highway 59 and Arkansas SH 246, then flows about 28.6 miles southwest to Broken Bow Lake in McCurtain County, Oklahoma.
This is a wide river with occasional ledges and long pools -- classic pool-and-drop river. It flows down shallow gradient of 8-10 fpm in a riverbed consisting of rock ledges that create small drops and long pools of flatwater. The stream is very popular with kayakers and canoeists because of its remote feel, excellent scenery and potentially exciting whitewater.
The listed run can be split as three sections, the most popular section being a run of about 9 miles between US Highway 259 at Smithville, Oklahoma through "The Narrows" at the top of Broken Bow Lake, where the larger drops are situated. This begins with the _Toilet Bowl_ and ends with several ledges before the takeout.
Below Broken Bow Lake, it becomes the Lower Mountain Fork as it flows out of the dam below the lake at the power plant. The river slows considerably for about 5 miles between the power plant and the rereg dam, where the whitewater section of the
Lower Mountain Fork begins.