the scarce 1849 Samuel Augustus Mitchell Map of Texas. Based upon the Tanner/Burroughs map of 1847, this map covers all of Texas according to the original 1836 claims of the Republic of Texas. This includes a fast territory extending from the western Rio Grande to the Sabine River and from the Arkansas River to the mouth of the Rio Grande as it enters the Gulf of Mexico. This included much of modern day New Mexico as far west as Santa Fe. Here the map is clearly divided between Bexar County, in yellow, and the more populated parts of Teas to the east. The county structure there is sophisticated and reflects numerous updates and revisions over the original 1847 Tanner plate. One year after this map was issued the Compromise of 1850, in which much of Texas's western territory would be sacrificed to the federal government in exchange for that entity paying of the state's war debt, dramatically and permanently changed Texas's cartographic profile. This map was issued in the 1849 edition of the New Universal Atlas. It was the last edition of that atlas to be published by Mitchell prior to selling the plates and rights to the atlas to Thomas Cowperthwait in 1850.