The United States extending west across the continental divide, with good (if not totally accurate) detail on the headwaters of the Missouri and other western areas. Texas is named, a small province along the Gulf coast, with Galveston at the eastern end, San Antonio in the west. Wheat notes that "...to the west stretches the vast expanse of `Missouri Territory.' Near the headwaters of the Platte appears the `Highest Peak," with the headwaters of the Arkansas River still west of that point, and those of the Rio del Norte (Rio Grande) west of that. The Rio del Norte nearly touches the sources of the Multnomah." From the third edition of Lavoisne's Genealogical, Historical, Chronological and Geographic Atlas; the map is on fairly thick paper, nicely engraved by B. Tanner. Wheat Transmississippi 338 notes the map as being dated 1820, but the date on this map has been changed in the plate.