Montana's first gold rush began near Bannack at Grasshopper Creek in the summer of 1862, when prospectors John White and company, camped along the insect-infested banks while looking for a shortcut to the Deer Lodge valley, panned the gravel and found color. Miners then swarmed to the new placers, and Bannack quickly sprang up as a rip-roaring settlement. The Civil War divided the town into Jeff Davis Gulch and Yankee Flats. By fall its population was 500, eventually rising to 5,000. When Montana Territory was created in 1864, Governor Sidney Edgerton designated Bannack the temporary capital and called the first legislature there in December, but gold discoveries at Alder Gulch drew away Bannack's residents and the territorial capital moved to Virginia City. Bannack was also the scene of several vigilante hangings in 1864, including that of sheriff Henry Plummer. It remained the Beaverhead County seat until 1881, by which time few people remained, though some continued mining for gold by different methods until 1954, when the state of Montana acquired most of the town. It later became a state park and was designated a National Historic Landmark in 1961.