Where the Great River of the North has cut through the narrow between the Franklin Mountains of Texas and New Mexico’s Sierra de Cristo Rey stands a twelve-foot high white pyramid. Designated by the International Boundary Commission "Boundary Monument No. 1" it bears witness to a point that lies about 500 feet to the east and in the center of the stream, where the United States and Mexico mark the transition of their common river boundary to a 698 miles long land boundary (except for 24 miles along the Colorado River). A hundred feet upstream at American Dam the Rio Grande loses most of its water into the Franklin Canal, leaving an anemic river mainly with the annual 60,000 acre-feet that by treaty belong to Mexico. After having squandered a mile and a half of elevation in the first third of its course the river depends on the remaining 3,676 feet to carry it for another 1,253.7 miles to the Gulf of Mexico.
This is the storied Pass of the North, the historic gateway for missionaries, soldiers, settlers, and traders traveling the Camino Real (the royal highway) between Mexico and Santa Fe. The east bank of the river is in Texas within the city limits of El Paso. To the west and south lies Ciudad Juarez in the Mexican state of Chihuahua, its dusty northern shantytowns slowly creeping into a group of hills that reach their highest point 1,300 feet north of the international boundary in New Mexico on Mount Cristo Rey. Since 1939 the Mount is adorned with a cream-colored limestone statue of Christ on a thirty-three foot high cross.
A thousand feet below, the Rio Grande ran deep and strong when in January 1855 surveyors of the International Boundary Commission marked where it was intersected by latitude thirty-one degrees and forty-seven minutes. Astronomical observations had been made some two miles northwest at Frontera and the geographic position computed on Bessel’s spheroid of 1841. Distances were carried by triangulation from base lines measured with two iron rods, each four meters long and calibrated by the U.S. Coast Survey. On an alluvial bench and 233 feet west of the center of the river they erected a pyramid of cut stone, five feet square at the base, twelve feet high, and thirty inches square near the top. The north side was inscribed: "U.S. Boundary according to the treaty of December 30, 1853." The south side bore a similar inscription in Spanish. The names of the two commissioner-surveyors were on the east and west: William Hemsley Emory for the U.S. and Jose Salazar Illaregui for Mexico.
The treaty referred to is the Gadsden Purchase, in Mexico known as the Treaty of Mesilla. It was Senator James Mason of Virginia, chairman of the Foreign Relations Committee, who proposed this latitude for the northern terminus of a boundary that starts in the Gulf of Mexico, three miles from land, and follows the center of the Rio Grande upstream.
Emory’s original monument was still in fair condition and needed only repair when the international boundary was resurveyed and monumented with six-foot high iron columns in 1892. To give it some protection it was enclosed with a wrought iron fence. Since 1855 the river had moved toward the east and the marker was now 500 feet to the west of it. In 1926 the pyramid was plastered and painted white. The Mexican section of what by now had been designated the International Boundary and Water Commission removed the fence in 1966 and surrounded the monument with a concrete platform. The most recent restoration was performed in 1989, at which time a bilingual interpretive plaque was added,
In 1972 this interesting site was turned into a public park, though mostly on the Mexican side of the boundary where Mexican President Francisco Madero had his headquarters in a small adobe house at the start of the 1911 revolution. Not easy to access, interest soon waned and the site was allowed to deteriorate until today it has a somewhat forlorn appearance.
Yet the area is steeped in history and well worth a visit. From I-10 take the Executive Center Blvd. exit at milepost 16 and drive 0.4 mile southwest to Paisano Street (old U.S. 85). A hundred yards to the south and almost beneath an abandoned steel railroad bridge of the Southern Pacific is a low, narrow bridge with a wooden deck, leading to a brick, yard on the New Mexico side of the river. From there it’s a quarter mile on a gravel road that dead-ends at the monument. Bridge and access road are on private property and permission should be obtained from American Eagle Brick Co. whose offices are nearby. Look respectable; the U.S. Border Patrol will keep an eye on you.