BORDER MONUMENTS

After the war between the United States and Mexico, much of Southern Arizona was still a part of Mexico.  The original southern boundary of the United States was established by the Treaty of Guadelupe Hidalgo which was signed on 2 February 1848 and ratified by the U.S. Senate on 10 March 1848.  The treaty poorly defined the U.S./Mexico border in the area of southern New Mexico west of the Rio Grande and in much of southern Arizona except that it was to follow the Gila River to the Colorado River.  The U.S. wanted to insure U.S. possession of the Mesilla Valley near the Rio Grande (the area west of Yuma) as the most practicable route for a southern railway to California.

In 1853, James Gadsden negotiated a treaty with the Mexican Government, which purchased 30,000 square miles of territory for ten million dollars.  The treaty was ratified in 1854 and established a new southern boundary between the cities of El Paso Texas and Yuma Arizona.

The boundary west of the Rio Grande is delineated by 205 monuments.  Some of the monuments have been in place since 1855 but most were constructed during 1893 and 1894.  There were few or no roads in the Pajarito Mountains in the 1890s so construction was quite difficult.  It was documented that “the pieces for Monument 128 and the cement for its base was carried on pack mules 22 miles over very difficult mountain trails.  The water was carried 9 miles and the sand 2 miles.

The Green Valley Hiking Club normally visits three of these border monuments, numbers 126, 127 and 128.  These three monuments are spaced relatively close together and define the 20 degree bend in the Arizona border just to the west of Nogales.  The bend was created so that Sonora and Baja California would be connected by land.  If this had not been done, Rocky Point would be in Arizona.

Monument 126 was placed at an elevation of 5300 feet and Monument 128 at an elevation of 5453 feet, the two highest points along the entire U.S./Mexican border.  Monument 127 is located at the precise point of the bend in the border.

During 1983 and 1984, Professor Robert Humphrey of the University of Arizona took on a project to photograph all of the border monuments between El Paso and Yuma with the purpose of comparing these pictures with photographs that had been taken during the original construction of the monuments. The intent was to see how the vegetation changed in the vicinity of the monuments over the 90-year period.  He was able to take pictures of all but one of the 205 monuments


Summary prepared by T. Johnson from information extracted from the book 90 Years and 535 Miles by Professor Robert Humphry and from various Web sites pertaining to the Treaty of Guadelupe Hidalgo and the Gadsden Purchase.

Additional Material: GVHC Library File 17