True first edtion of this map, which shows Dacotah Territory extending to the Missouri Missouri River, with a massive Nebraska Territory. Dacotah Territory is filled with Indian lands, naming no less than 5 different bands of Dakota Indians, as well as many others. Nice detail along the Missouri and its Tributatries. Several early forts are noted including Ft. Pierre, Ft. Lookout, Ft. Clarke, and Ft. Berthold. A number of counties are still note formed in Minnesota. Stevens route is shown for the Northern Pacific., along with existing and other proposed rail lines. Massive Nebraska Territory is shown west of the Missouri.
Samuel Augustus Mitchell Jr. inherited the Mitchell Company from his father in 1860. For over thirty years, the company had specialized in the production of school atlases and wall maps of America. They were one of the pioneers on engraving on steel plates. In 1860, Samuel Jr. released the New General Atlas, which had been compiled in house and replaced a previous atlas by Tanner. The elder Mitchell died in 1868 and Samuel Jr. continued the business until the 1890s. At its height, the Mitchell Company employed 250 people and sold 400,000 publications annually.