Chimney Rock is a prominent geological rock formation in Morrill County in western Nebraska. Rising nearly 300 feet (91 m) above the surrounding North Platte River valley, the peak of Chimney Rock is 4,228 feet (1,289 m) above sea level. The formation served as a landmark along the Oregon Trail, the California Trail, and the Mormon Trail during the mid-19th century. The trails ran along the north side of the rock, which remains a visible landmark for modern travelers along U.S. Route 26 and Nebraska Highway 92. Chimney Rock National Historic Site was designated in 1956 and is an affiliated area of the National Park Service, operated by History Nebraska. Chimney Rock was added to the National Register of Historic Places on October 15, 1966. History Prior to exploration and settlement by European immigrants, the Native Americans of the area—mainly the Lakota Sioux—would refer to this formation by a term which meant "elk penis". The first non-natives to see the pillar were probably the Astorians of Robert Stuart in their eastward journey from the Pacific Ocean in 1813. Chimney Rock was recorded in many journals after the Stuart...