In writing about the boundaries of our state in previous columns I concerned myself primarily with the surveys, which put these lines on the ground. In doing so I ignored the evolvement of the legal definition of these lines as established by congressional action. The reader may well ask: "Whatever happened to the historic boundaries of the Mexican Territory of Nuevo Mexico?" The answer: They took quite a beating.
New Mexico fared best with its south boundary, which was defined in the treaty of Guadalupe-Hidalgo  and the Gadsden Purchase . No portion of today’s international boundary infringes on land historically included in the Spanish province of Nuevo Mexico and later in the Mexican territory of that name. In addition, as a result of the Gadsden Purchase New Mexico gained territory, which had been a portion of the Mexican states of Chihuahua and Sonora.
So much for the good news, and now the other. On our west and east New Mexico’s boundaries theoretically coincided with those of Spanish California and Spanish Texas. Since the primarily coastal settlements in both of these regions were separated from those on the upper Rio Grande by hundreds of miles of deserts and mountains, sparsely occupied by nomadic Indians hostile to Spanish control, an administrative definition of these boundaries was mood and never attempted. Since the early 1700’s the governors of Nuevo Mexico sent numerous military expeditions for explorative and punitive purposes into the surrounding areas but colonization and settlement was clearly impossible. It goes without saying that neither of these limits were ever defined by a meridian of longitude as they are today.
New Mexico’s north and northeast however is a different matter and deserves a closer examination. The treaty of February 22, 1819 with Spain established the Arkansas River as boundary between the United States and the Spanish possessions. Maps of the period show New Mexico to extend north to the Arkansas and to include the entire watershed of the Rio Grande. The Disturnell map of 1847, referred to in the treaty of Guadalupe-Hidalgo, shows New Mexico as extending north to latitude 40 degrees and including the Rio Grande basin.
At the time of the American occupation of New Mexico there were no permanent settlements north of latitude 37 degrees. In 1844 Governor Armijo granted a petition made by Cornelio Vigil and Ceran St. Vrain for 4 million acres (Las Animas Grant). The grant extended from the Arkansas River through what is now southern Colorado all the way to the north boundary of the Maxwell Grant, all of which was considered to be located in Taos County, New Mexico. In a rare exercise of good judgment Congress reduced Governor Armijo’s largesse to the roughly 95,000-acre maximum (eleven square leagues or about 47,700 acres for each applicant) allowable under Spanish law. Other land grants that were all or in part made north of latitude 37 degrees and considered located in New Mexico were the Tierra Amarilla, Conejos, Sangre de Cristo, Gervacio Nolan (Rio Don Carlos Grant, also greatly reduced in size by Congress), and Beaubien & Miranda (Maxwell).
After the American occupation and the organization of civilian government (under more or less military control) the boundaries of New Mexico were of immediate concern to the authorities in Santa Fe. Already in October 1848 in a memorial drafted at a convention of influential citizens in that city the attendees protested against any dismemberment of the territory "in favor of Texas or for any [other] cause." When nineteen elected delegates met in Santa Fe in September of the following year they defined the boundaries of New Mexico as being "north by the Indian Territory; west by California; …and east by the state of Texas," it being understood that the Texas claim to the Rio Grande as her boundary was preposterous. At a constitutional convention held in May 1850 in Santa Fe the delegates were more specific, claiming for New Mexico the entire Texas and Oklahoma panhandles east to the 100th meridian, along the 100th meridian to the Arkansas and along that river all the way to its source.
Of the Texas claim to "Santa Fe County" I have written previously [NEWSLETTER MAY 1992] and will not reiterate here. The Civil War might easily have started in 1850 when Texas was preparing to raise an army to settle the boundary question by force. For that reason the definition of New Mexico’s boundary acquired a distinct urgency in Congress. The debates were lengthy and bitter, reflecting the division of the country over the slavery issue. It was Senator James Pearce of Maryland who suggested placing New Mexico’s east boundary at the 103rd meridian and compensating Texas with 10 million dollars. In an amendment to Senate bill 170, calling for the creation of the Territory of New Mexico, Senator Douglas of Illinois defined the entire boundaries of New Mexico. As finally adopted they read in part (9 Stat. L. 447): "…thence north with said degree of longitude [103rd] to the parallel of thirty-eight [emphasis added] degrees of north latitude; thence west with said parallel to the summit of the Sierra Madre; thence south with the crest of said mountains to the thirty-seventh parallel…" This description includes the San Luis Valley of Colorado, the entire Rio Grande watershed, and all of the watershed of the Purgatoire and most of that of the Huerfano rivers, clipping the bend of the Arkansas River at present La Junta.
There was considerable uncertainty as to what mountain range was meant by Sierra Madre. On old maps the San Juan Mountains along the Continental Divide between 37 and 38 degree latitude are generally referred to as Sierra Madre, but some maps assign that name to the Sangre de Cristo range east of the Rio Grande. William Emory applied it to the Continental Divide, as did the War Department in an official map of 1857. When the U.S. Army built Fort Massachusetts in 1852 in a swampy hollow about six miles north of what is now Fort Garland, it was put under the jurisdiction of the Department of New Mexico. The 1860 national census lists all towns in the San Luis valley as parts of Taos County.
Settlement in that area had been a risky business attempted since the early 1700’s. French trappers from Louisiana as well as Spanish colonial authorities tried their best to establish a permanent foothold, but the Indians (primarily the Utes) were able to annihilate all who were foolhardy enough to venture so far from the relative safety of the Taos valley. The Spaniards even tried to get the Indians themselves to settle in permanent villages but all attempts were in vain. As late as 1846 the Ute Indians were able to drive yet another batch of colonists back into Taos. Only with the coming of the U.S. cavalry in the early 1850s was permanent settlement possible, the first successful attempt occurring in 1851 at what became the town of San Luis.
New Mexico lawmakers were in no way pleased with the "Compromise of 1850" that created and defined the boundaries of New Mexico Territory, but there was little they could do. Attempts at statehood had been frustrated by the untimely death of President Taylor in July 1850 and by the failure, despite all efforts, to keep New Mexico out of the sectional controversy. But more had been lost than met the eye. Substituting the arbitrary latitude of 38 degrees for the historic call for the Arkansas River seemed of minor consequence to the layman looking at a map, however by replacing a natural boundary with an artificial one it set the stage for yet another reduction.
Adjoining New Mexico, the area north of the Arkansas River was vaguely part of Arapaho County in Kansas Territory and was generally referred to as Pikes Peak country. Miners, traders, ranchers and adventurers poured into the area from the east, hungry for the free mineral wealth and free public land, and not inclined to worry about boundaries. In 1858 an attempt was made by Colorado City civic leaders to organize the "State of Jefferson", but by popular vote a year later it was decided to organize a territorial government instead, and soon a provisional governor and a legislature were elected. These people had strong roots in the American political system and had no desire to be governed from Santa Fe. If they went to Taos, still the nominal county seat, it was for the almost exclusive purpose of buying whiskey (Taos Lightning) or to marry New Mexican girls.
Colorado (the name was coined in the Senate) was organized as a Territory with its south boundary extending along the 37th parallel on February 28, 1861 (12 Stat. L. 172). This action sliced a full degree of latitude off New Mexico’s top, from the 103rd meridian on the east to the continental divide on the west, an area known as the New Mexico notch.
Only ten days earlier Jefferson Davis had been inaugurated President of the newly formed Confederate States of America and Colorado was thought to be solid Union territory. New Mexico’s slave code, enacted in 1859, led most people to believe that the territory had accepted slavery and was sympathetic to the Confederacy. Delegate Miguel Otero, father of the future Governor, and Senator Stephen Douglas, creator of New Mexico’s original boundaries, tried in vain to defeat the reduction of its land area. Douglas too had assumed that the New Mexico notch had been slave territory, causing Senator Green of Missouri to counter, that the Colorado bill "does not cut off five inhabitants, and not a single n. (obscenity deleted)." In fact, New Mexico governor Connelly (1861-1865) estimated that the New Mexico notch had a population of about 4,000. But the governor was helpless and could only express his regret that Colorado had taken the "fairest portion of our northern boundary" and to state his conviction that statehood was the only way of preventing the territory’s gradual shrinking in size.
Yet when another blow fell only two years later with the creation of Arizona Territory it was accepted in Santa Fe with apparent indifference. The Civil War was raging and Confederate conquest as well as Confederate partition of the Territory had narrowly been averted. Congress had more important things to worry about than the size of New Mexico Territory. Later the arguments focused on the infinite smaller amounts of land lost in faulty surveys and on the validity of Spanish land grants. Also, many public officials had grown weary of New Mexico’s never ending land and boundary problems and were slow to lend sorely needed support. General Sherman even went so far as to suggest in the House of Representatives to prevail upon the Republic of Mexico to take back the territory.
It can of course be argued that New Mexico’s settled core was unaffected by its receding boundary and that its citizens lacked both the ability and the will to more vigorously defend the limits of their historic homeland against outside encroachment. But this is another subject and outside the scope of this article.