Map of Kansas, Nebraska, Colorado, & Southern Portion of Dacotah, 1861

Most of the area that now is Wyoming, except for a small attachment remaining with Idaho territory, became part of Dakota territory in May of 1864, for a four year period until Wyoming, itself, became a territory in 1868. Note the lightly engraved "Attached to Dakotah". This is an updated version of an A. J. Mitchell map with and 1861 copyright date.