This was the critical map of the Mexican Boundary Survey. Initial work had broken down over a Mexican demand that Mexico be given the port of San Diego and the determination of the length of a league. It provides interesting detail in the vicinity of San Diego and anchors the border determination for this area. This map is full of information, including the new Camp Rough & Ready, which became a gold mining town and then seceded as a republic for about three months in 1850, until the neighboring towns started having 4th of July celebrations and they felt left out and rejoined the country. The map is visually very attractive with calligraphy title and a large compass rose. Marine leagues are described on the map as 5564 meters - the standard today. Surveyed by Andrew B. Gray, John B. Weller, Commissioner.

References: Wheat (TMW) #616.

Condition: A

A clean and bright example, issued folding with a binding trim in the left blank margin that has been replaced with old paper and an adjacent tiny chip long the neatline that has been archivally repaired. There are a couple of short fold separations that just enter the neatline at top and have been closed on verso with archival tape, and marginal toning along the top edge of the sheet.