Rocky Bar is a ghost town in Elmore County, Idaho, United States. At its height in the late 19th century Rocky Bar boasted a population of over 2,500 and served as county seat of Alturas County from 1864 to 1882. It was also the original county seat of Elmore County when it was created in 1889.
Rocky Bar was founded in December 1863 soon after gold was discovered along the nearby Feather River. Within two years it became the main settlement in the area and was even considered as a possible capital for Idaho Territory. The town was destroyed by fire in 1892. Although it was rebuilt, afterwards it began a slow decline. Rocky Bar has not had a permanent population since the 1960s.