Casey Creek (Illinois) and Atchison Creek. Gun Creek, which enters Rend Lake on the east side, might also be considered a Casey Creek tributary. Casey Creek (Illinois) Casey Creek is a major tributary of the Big Muddy River in Illinois, United States. It is about long, measured from the junction of its arm of Rend Lake with the arm formed by the Big Muddy River. Casey Creek is shown on federal maps as Casey Fork, following a 1967 decision by the U.S. Board on Geographic Names. It is named for Zadok Casey, a congressman from Illinois in the early 19th century. Casey Creek
Muddy River (Washington) 83 and passes the Ape Canyon Trailhead and the Lava Canyon Interpretive Site, both on the left, before entering Muddy River Gorge. Flowing northeast through the gorge, the stream plunges over three waterfalls before emerging from the narrows and curving sharply again to the southeast. Here Crane Lake is on the left, Smith Creek enters from the left, and Smith Creek Trailhead is on the right. Slightly downstream of the trailhead, the river leaves the national volcanic monument but remains in the national forest. At about the level, Clearwater Creek enters from the left. Turning south, the river descends less