“Humboldt, who during his lifetime was considered the world's greatest living man, composed this map during his 1803 sojourn in New Spain (Mexico). Covering from Alta California to Connecticut and from the Great Salt Lake (here Timpanagos) to Honduras...[this map outlines]...the territory that in the coming years would be subsumed into the expanding United States. Humboldt spent part of 1803 and 1804 living in Mexico City as a guest of the Spanish Crown. As such he had access to rarely seen explorer's accounts and earlier mappings available in the Mexico City archives. These he combined with information from his own travels and explorations, as well as indigenous cartographic traditions and his own theoretical understanding of geography, to create this landmark mapping of the North American southwest…” wikipedia.org
stanford.edu humboldt.edu-1 humboldt.edu-2