A nice hand colored map of the northwest, with an enlarged Idaho Territory incorporating present-day western Montana. Gold discoveries in Clearwater Country, Idaho, in September 1860 led to an influx of thousand of miners into the region. Idaho was organized as a territory in July 1863 and Montana was separated as a territory in May 1864, thus this map was issued for only a short period of time. The area of the Solomon River and the New Pierce mines are shown.