The storied Army Corps of Topographical Engineers were a hand-picked group of West Point graduates. In their short life span of only twenty-three years as a separate corps, they probably did more, in proportion to their small numbers, than any other group. The Corps was a combination of science and romance, the prototypes of the original seven astronauts of the 1960s.
When the Mexican War ended in 1848, neither side knew which part of the territory had been won and lost. Only a few hard-scrabble mud adobe villages existed in the rugged, unexplored regions of today’s Southwest. It was a blank on the map of North America. The only known chart of the area was drawn in 1847 by John Disturnell and it proved to be inaccurate.
Article V of the Treaty of Guadalupe Hidalgo stipulated that a joint Mexican-American boundary survey would be conducted to establish an international border-line between the two nations.
When the two boundary commissioners were appointed by the United States and Mexico to survey the 800 miles of the Mexican border from El Paso to San Diego.
Mexico, to its credit, selected its foremost engineer, General Pedro Garcia Conde, to represent their interests. The U.S. chose as its boundary commissioner, a political appointee, John Russell Bartlett, of Rhode Island, a part-owner of a bookstore. By his own words, he’d led a sedentary life and wanted to travel. He also had a great interest in American Indians, whom he’d never seen in their native habitat. For the next two and one-half years, he and his expensive entourage of 111 civilian “greenhorns” and 85 military personal would travel extensively in the Southwest, Mexico and California spending as little time as possible on the business of establishing a boundary.
This match between boundary commissioners would be comparable to pitting Fatty Arbuckle against Babe Ruth in a home run derby.
For Bartlett the boundary survey was always of secondary importance. He was gathering material to write a book. Of the $500,000 spent by Bartlett’s commission only $100,000 went towards the actual survey.
Fortunately for the U.S. Major William Emory of the Army Corps of Topographical Engineers accompanied the boundary party. The 39-year-old officer was the most brilliant topographical engineer in the U.S. He was asked to be Boundary Commissioner but he declined the offer because he didn’t wish to resign his commission. He did agree to be chief astronomer and cartographer.
The hapless Boundary Commissioner was blessed with a competent surveyor, Andrew B. Gray, who later wrote four-fifths of Bartlett’s entourage was utterly useless.
Nickolas Trist, the U.S. Treaty of Guadalupe Hidalgo negotiator, had used the Disturnell map that placed El Paso del Norte forty-two miles further north and 100 miles east of its actual location. Bartlett was prepared to give up that land despite knowing the map was faulty.
In order to finalize the agreement both commissioners and surveyors had to sign off on it. Bartlett signed but Gray refused to sign. Both he, Emory and Lt. Amiel Whipple agreed the land being given to the Mexicans was vital to the building of a railroad. At the time the Mexican-American border followed the Gila River across today’s Arizona to the Colorado River then west to San Diego.
Both Bartlett and Gray wrote letters to Washington defending their positions. Since it would be months before the issue would be resolved, Bartlett took off on a lengthy sight-seeing excursion while the engineers continued their boundary work.
The issue over the Mesilla Valley was not settled and for a time it looked like the two nations would go to war again. The boundary survey was virtually teetering on total collapse. In 1853 a railroad man named James Gadsden, was sent to Mexico to purchase an additional 29,640 square miles of land south of the Gila River. The Gadsden Purchase, ratified by Congress in 1854, would be the last region added to the Continental United States. A few years later the Southern Pacific Railroad would build a transcontinental line through the new acquisition.
Marshall Trimble is Arizona’s official historian and the Wild West History Association’s vice president. His latest book is 2018’s Arizona Oddities: A Land of Anomalies and Tamales. Send your question, with your city/state of residence, to marshall.trimble@