Prologue Magazine

Monuments, Manifest Destiny, and Mexico

En Español

Summer 2005, Vol. 37, No. 2

By Michael Dear

© 2005 by Michael Dear

Disturnell map of U.S.-Mexico Border
The Disturnell map of 1847 was appended to the Treaty of Guadalupe Hidalgo. (General Records of the U.S. Government, RG 11) [larger image]

The survey of the U.S.-Mexico borderline, which followed the 1848 Treaty of Guadalupe Hidalgo, is sometimes disparagingly referred to as the stuff that "dime novels" are made of. To justify this characterization, some historians invoke tales of political intrigue, deaths from starvation and yellow fever, struggles for survival in the desert, and the constant threat of violent attacks by Indians and filibusters.

Yet, truth be told, the mid-19th century survey of the 2,000-mile border was a story of heroism, skill, and endurance of epic proportions. Though lacking the glamour of war or the grandeur of the Lewis and Clark expedition, the boundary survey is one of the greatest events in U.S. political history and remains deeply present in our contemporary lives.

Dime novel it's not; it is more a narrative of nation-building, centered in President James K. Polk's vision of manifest destiny.


The Treaty of Guadalupe Hidalgo and Its Aftermath


The Treaty of Guadalupe Hidalgo, as it came to be called, was the outcome of a protracted series of negotiations between the two nations. On the U.S. side, Nicholas Trist proved to be an effective and sympathetic negotiator, who courageously ignored a recall notice from an irate President Polk (who believed Trist had conceded too much to the Mexicans) in order to complete discussions and sign the treaty. On the Mexican side, interim President Manuel de la Peña y Peña played a very important role by prevailing on Trist to stay on the job despite Polk's wrath and by bringing together warring factions at home to accept compromise.

Presented with a signed treaty, an outraged Polk feared the political consequences of repudiating it, and the treaty was eventually proclaimed on July 4, 1848. Mexico had gained peace and $15 million, but had lost one-half of its territory; and the United States had achieved the most important belligerent land grab in its history. The heroic Nicholas Trist returned to Washington, D.C., only to be cruelly ignored by President Polk.

In her definitive account of the making of the U.S.-Mexico boundary, Paula Rebert notes how the treaty accomplished two tasks essential to the integrity of la línea: the allocation of territory and the delimitation of the boundary. But these tasks were only the beginning. Also important were demarcation (locating and marking the boundary on the ground), map-making (to document the line), and maintenance and administration of the line thereafter.

The Treaty of Guadalupe Hidalgo required the designation of a "boundary line with due precision, upon authoritative maps, and to establish upon the ground landmarks which shall show the limits of both republics." The line would extend from the mouth of the deepest channel of the Rio Grande (also known as the Río Bravo del Norte); up the river to "the town called Paso" (present-day Ciudad Juárez); from thence overland to the Gila River, and down the channel of the Colorado River; after which it would follow the division between Upper (Alta) California and Lower (Baja) California to the Pacific Ocean.

The surveys themselves took six years to complete, beginning in 1849 and ending in 1855. Four separate boundary commissions were established by each country, the first three based principally in Paso and San Diego and charged with surveying different geographical sections of the 2,000-mile survey. The fourth commission was jointly convened in Washington, D.C., in 1856–1857 in order to complete mapmaking of the boundary line.

Detail of 4th commission's map of US-Mexico boundary at El Paso del Norte
Detail of one of the 54 survey maps from the fourth boundary commission (a view of the initial point on the Rio Bravo del Norte). The full map shows the U.S.-Mexico boundary in the El Paso del Norte District. (Records of the Boundary and Claims Commissions and Arbitrations, RG 76)

The various U.S. field surveys were plagued by acrimony and personal vendettas. In historian Carl Wheat's assessment: "if ever a mapping enterprise in the American West was cursed by politics, interdepartmental rivalries, and personal jealousies, it was the Mexican Boundary Survey." Certainly, the letters, diaries, and official memorandums by individuals involved on the U.S. side of the survey portray every other American participant as either a scoundrel or a self-promoter.

In contrast, the relationship between the U.S. and Mexican survey teams is reported as a paragon of rectitude and courtesy. At the close of the survey, the U.S. commissioner was able to write that "the utmost harmony has existed on this Commission between the Officers of both governments, and that all questions likely to produce the least difference have been settled harmoniously."

Such harmony was hard-won. The U.S. commissioner, William Hemsley Emory (known as "Bold Emory" by his contemporaries), and his Mexican counterpart, Commissioner José Salazar y Larregui ("a charming person, active, intelligent and polite,"according to Wheat) had together labored for many years, enduring perils, physical hardships, and the trials imposed by their political masters. They were also hindered by flaws in the treaty as well as by the borderlands' capricious geography. Most problematic was the treaty's specification that the land boundary from the Rio Grande was to strike west at a point eight miles north of Paso. However, the Disturnell map (appended to the treaty) showed Paso at a point 42 miles north of its true position. Disputes over the precise location for the land boundary after it parted from the river were not resolved until the Treaty of 1853, known as the Gadsden Purchase in the United States and as the Treaty of Mesilla in Mexico.

Surprises of geography caused other unexpected amendments to the line. The western end was designated as "one marine league due south of the southernmost point of the Port of San " from which it was to run eastward in a straight line to the confluence of the Gila and Colorado Rivers. The problem was that below the confluence, the Colorado took a sudden northward swing before bending south again to the Gulf of California. Had the straight line to the confluence been adhered to, a large crescent of land on the Colorado's south bank would have been allocated to the United States. Later adjustments placed the boundary where it first intersected with the Colorado, thus eliminating the Gila-Colorado confluence from further consideration.

On December 18, 1855, Commissioner Emory wrote to Washington, D.C.: "The field work of the boundary commission is . . . at an end." The successful completion of the 2000-mile survey was testimony to the enormous skill and endurance of the two longest-serving commission personnel: Emory and Salazar. The two men met again in Washington, D.C., under the auspices of the fourth boundary commission in order to complete the making of 54 survey maps. On September 21, 1857, they signed the final maps, and the boundary survey was officially adjourned. However, international disputes about the exact placement of the border continued for more than a century, and the line marked on the ground by the commissioners, in the form of boundary monuments, was to play a critically important role in resolving the burgeoning disputes between the United States and Mexico.

Marking the Line, 1849–1855

The boundary survey began on July 6, 1849, just south of the port of San Diego. For the next six years, U.S. and Mexican survey teams crisscrossed the borderlands, sometimes working collaboratively, other times independently, but always meeting regularly to confirm each others' work. Broadly speaking, the survey was undertaken in three sections, which were not in orderly sequence but instead varied in location according to the exigencies of physical hardship, uncertain supplies, and political winds in the respective national capitals.

  1. Between 1849 and 1851, the California survey was completed, from San Diego to the Colorado River.
  2. In 1851, Rio Grande survey teams began trekking downstream from Paso, only to be halted at Big Bend and beyond; the river survey began again in 1853, this time proceeding upstream from an initial point on the Gulf of Mexico, and was completed later that year by U.S. surveyors.
  3. Finally, a land survey between Paso and the Colorado River was relatively swiftly executed in 1855, once the initial point above Paso was settled by the Treaty of 1853.

As the surveys commenced, primary attention was understandably lavished on fixing the initial points (puntos iniciales) of the boundary line: at San Diego, the confluence of the Gila and Colorado Rivers, Paso, and the mouth (desembocadura) of the Rio Grande. In June 1849 the first U.S. boundary commissioner, John B. Weller, arrived in San Diego, accompanied by surveyor Andrew Belcher Gray and Maj. William Emory, then chief astronomer and head of the Topographical Scientific Corps. They were joined a month later by Mexican Commissioner General Pedro García Conde and surveyor José Salazar y Larregui. Emory and Salazar were enjoined to determine the first punto inicial "one marine league" south of the port of San Diego, another at the Gila-Colorado confluence, and to connect and mark these points with a straight line.

Disagreements arose immediately, since there was no standard measurement for a marine league. However, with a generous concordance that was to mark their entire collaboration, Salazar and Emory agreed to split the difference between their measurements. A location for the initial point was settled, and a temporary monument erected. The running of the line could begin.

Meantime, another U.S. survey team under Lt. Amiel Weeks Whipple headed out to establish an observatory at the Gila-Colorado confluence. Whipple built a stone monument on the first hill west of the confluence, and two more in the immediate vicinity. Emory and Salazar took charge of extending the line eastward from San Diego towards Whipple's mark. They constructed the first official boundary monument just east of the initial point in San Diego, where the line intersected the road to Baja California. As the line was run eastward, six other stations were noted on the maps of their survey.

In 1851, the two commissions met in Paso and drew up a formal plan of survey for the Rio Grande. However, this was followed only fitfully by scattered surveys until the arrival of Emory and Salazar (now Mexican commissioner following the death of Conde) in the summer of 1852. They divided the river into six sections: two each to be surveyed by respective national teams; and the first and last to be jointly executed. The eastern limit of the line, where the Rio Grande emptied into the Gulf, posed special difficulties because of the multiple shifting channels of the river.

Even after the deepest channel had been identified, problems remained because unstable dunes on either side of the desembocadura made it difficult to select sites for the two marble monuments planned for either side of the river. Eventually, two high dunes at the same astronomical meridian were selected. Reflecting some contention between the sides regarding the topographical measurements, the Mexican map of the desembocadura portrays both monument and river boundary, but the U.S. equivalent shows neither.

The 700-mile land boundary between the Rio Grande and the Pacific Ocean was the last to be completed, primarily because it had to await the Treaty of 1853. That settlement fixed the locations of the initial points at Paso and the Colorado River (the latter thereby superseding the original Gila-Colorado confluence punto inicial). The California line, from San Diego to the Colorado, had earlier been established. Seven marble or cast-iron monuments had been erected between the coast and the Colorado River: two monuments at each end of the line; another at the New River (near present-day Mexicali); and the remaining two at visible points along the intervening mountains. The commissioners were satisfied that seven monuments would be sufficient because so much of the land between the Pacific and the Colorado was "barren and can never be cultivated by either party."

E.L.F. Hardcastle and Francisco Jiménez were charged with erecting the cast-iron monuments, which had been manufactured in San Diego. The task was unexpectedly arduous, given the conditions in the desert, and involved adjustment to the location of earlier markers around the New River. Because long expanses on the California line were left unmarked, Hardcastle and Ricardo Ramírez (who had succeeded Jiménez) placed several supplementary monuments of loose stone west of the New River.

By July 1851, a marble monument at the Pacific Ocean was approved, and the California survey was officially terminated. The following year (April 1852), John Russell Bartlett, who had spent most of his time as U.S. boundary commissioner on an extended (and expensive) tour of the American West, happened upon the Pacific monument. In his published reminiscences, he later described it as: "an obelisk about twenty feet in height . . . and is seen from a great distance on land as well as by vessels at sea."

Connecting the initial points from Paso to the Colorado River was now all that remained to be done. Since the land lines were mathematically defined in the Treaty of 1853, their demarcation was a relatively simple task. The 1853 treaty had reconstituted the U.S. Commission as a well-funded unit under Emory's leadership, but the Comisión de Límites Mexicana, led by the able Salazar, was chronically underfunded. (In a gesture of goodwill, Emory had discreetly secured funding from the U.S. in support of Salazar's work.) Matters were not helped when Salazar was imprisoned for a brief period at the behest of Mexican President Santa Anna. In any event, Emory initially proceeded alone with the survey westward from the Rio Grande, while Salazar and his small retinue remained in Paso to complete the placement of three permanent monuments.

Monuments, Manifest Destiny, and Mexico, Part 2



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