This map illustrates a critical aspect of the Mexican Boundary Survey (following the Treaty of Guadeloupe Hidalgo), with the determination of an agreed upon point, as the middle of the Rio Gila where it enters the Colorado, to anchor the boundary line in the east. Shows the villages of Captain Pasqual, Capt. Anastasio, and Captain Anton in the vicinity of Yuma. Also shows the Old Emigrant Route and General Kearney's Route. An important map and companion to the map of the Southernmost point of the Port of San Diego by Emory (see next lot).

References: Wheat (TMW) #653.

Condition: A

Issued folding, now backed with archival tissue. Trace of foxing and one small flaw, still very good.