Wyoming Highway 191 begins its western end in the community of Mayoworth, located northwest of Kaycee.

[2][3] From there WYO 191 travels southeast towards Kaycee.

Nearing its end the eastern terminus of Wyoming Highway 190 (Barnum Road), which serves the outlying community of Barnum, is intersected before meeting an interchange with I-25/US 87 at exit 254 in Kaycee.

[4] 0.16 miles (0.3 km) later WYO 191 reaches its eastern terminus at Wyoming Highway 196 and the western terminus of Wyoming Highway 192 (Sussex Road) in Kaycee.

[4] The entire route is in Johnson County.