AT A GLANCE
Why go?
The Cannonball River is a wild-feeling ribbon of water threading the badlands of southwestern North Dakota before it spills into the Missouri River's Lake Oahe reservoir. Rising in the Little Missouri National Grassland north of Amidon, it runs east-southeast past the small prairie towns of New England, Mott and Burt, gathers the Cedar Creek, then forms the northern edge of the Standing Rock Sioux Reservation on its final stretch to the big Missouri. Its mapped course is roughly 135 miles (217 km), though sources that trace the full meandering channel from the upper headwaters count it closer to 300 miles.↗↗
This is a river for the slow explorer: a place of eroded buttes, grassland winds, petrified-wood gravel and a name lifted straight out of the round stone 'cannonballs' scattered along its banks. Anglers work its pools for catfish and pike, paddlers reach it where it meets the Missouri, and the high badlands around its headwaters hold the very stones that gave it its name.↗↗
A River Named for Its Rocks
Stand on the Cannonball's banks and the name explains itself. Round, cannonball-shaped stone concretions litter the gravels here; they are the spherical rocks that early observers and the WPA guide noted as the river's signature, and that the Lakota name for the stream, Íŋyaŋwakağapi Wakpá, likewise evokes. Alongside them lie the harder treasures of the headwaters: the Rainy Buttes silicified (petrified) wood around East and West Rainy Buttes in Slope County, a distinctive dark reddish-brown stone, plus agatized wood and silcrete that prehistoric toolmakers prized across the northern plains.
