The North Popo Agie River (also known as the North Fork Popo Agie River) is a river in Fremont County, Wyoming, United States, that serves as part of the boundary of the Wind River Indian Reservation. Its headwaters are at Lonesome Lake in the Wind River Range, and it flows eastward until its end near Lander when it joins the Middle Popo Agie River to form the Popo Agie River.
The river is considered a Class 2 fishery by the Wyoming Game and Fish Department, meaning it has very good trout waters of statewide importance. Species found here include rainbow trout, brook trout, cutthroat trout and mountain whitefish.