The New World Mining District is an area of mineralization that sits within Gallatin National Forest to the northeast of Cooke City and Yellowstone National Park, in Park County, Montana, United States. The district hosts extensive deposits of gold, silver and copper in zones of carbonate replacement. These deposits are the result of Eocene hydrothermal alteration of Cambrian carbonates related to the Absaroka volcanic field. Alteration and mineralization occur primarily within carbonate clasts hosted in a volcanic breccia pipe and in carbonate rocks that lie adjacent to that breccia.