Fine example of the groundbreaking 1847 "Fourth Edition" of Tanner's map of Mexico, one of the most important maps in 19th Century American History, and the most influential general map of the Mexican-American War period.
This fascinating map embraces all of what was until 1848 the Republic of Mexico, which included the modern-day nation, plus large portions of what is now the American Southwest, including all of the future U.S. states of California, Arizona, New Mexico, Nevada, Utah, and parts of Texas, Oklahoma and Colorado.
According to Walter Ristow, Tanner produced the first edition of the United States of Mexico map in 1825, and he notes that he "issued 10 variants of one or another of five states" of the map up to 1847, plus another edition which was issued in 1850. Taken as a sequence, the evolution of Tanner's map graphically depicts on a single canvas the evolution of the Southwest from 1825 to 1850.
The early issues of the map were critically important records of European-American knowledge of the American Southwest. However, they were in good part based on the work of non-American sources, such as Alexander von Humboldt, and showed the region long before the United States had significant involvement in its affairs. Over time, as knowledge of the Southwest evolved, the source grew increasingly indigenous in nature.
Tanner based his 1825 map on the work of Alexander von Humboldt, Don Juan Pedro Walker, Zebulon M. Pike, William Darby, Bernardo de Orta, J.F. de Lángara y Huarte, and other sources. Tanner's map was often copied, both in the U.S. and abroad. Wheat noted that on the first edition of the map that "the southern boundary of New Mexico seems to follow Humboldt, but in 1826 Tanner altered that boundary west of El Paso, bringing it further north." It was this 1826 issue of the map that became the source for the White, Gallaher and White map of 1828, which in turn became the source for Disturnell's celebrated Mapa de los Estados Unidos de Mejico, first published in 1846, creating the erroneous boundary in the Treaty of Guadalupe Hidalgo.
Early in 1846, the ever-enterprising Tanner, hastily issued what he called a "Second Edition" to capitalize on the start of the Mexican American War (1846-48). The "Second Edition" was viewed to be deficient, as it did not feature many of the late-breaking discoveries, most notably Frémont's mapping of the interior Southwest. The present "Third Edition" was issued later in 1846, and is greatly improved from the previous effort.
Importantly, the present edition is the first to contain many groundbreaking American sources and to feature the region at the very time that it was at the epicenter of current affairs in the United States. It was by far the most important and influential general map depicting the theater of the conflict, which was arguably the most transformative event in 19th Century American History, whereupon the United States went from being a player on the Atlantic sphere to becoming a great World power stretched from sea to sea across North America. As such, the map would have been of great interest to the American public, which generally knew very little about Mexico or the Southwest. Far from merely informing observers about the basic geography of the war, the present map provides groundbreaking information and the finest contemporary overview of the region.
The political details of the map are most intriguing. Texas's official designation is shown to be somewhat ambiguous on the map, although notably, it is not included in the table of Mexican states in the left-hand portion of the map. Texas had seceded from Mexico to become an independent republic in 1836, and was annexed by the United States in 1845, an event that triggered open conflict between America and Mexico. The geographical detailing of most of Texas is quite accurate, based on Stephen F. Austin's 1830 map (which was also published by Tanner), a point underscored by the inclusion of 'Austin's Colony' in east-central Texas. Much of West Texas owes its form to William Emory's map of 1844, although Texas does not feature the famous "stovepipe" which is present on many maps of the period. Tanner's map embraces the Texan claims against New Mexico, which shows all of the left bank of the Rio Grande to be in Texas, including the New Mexican capital of Santa Fe. The Mexican state of Chihuahua extends north to embrace the southwestern part of modern New Mexico.
The remainder of the Southwest is shown to be a part of the Mexican region of Upper (Alta) California, which has a curious conjectural boundary with Lower (Baja) California, located well to the south of San Diego. While the mapping of the coastal northern California is quite well assured, the coastlines of Southern California are still charted in a very crude fashion.
Most importantly, the "Third Edition" is the first to feature the discoveries of John Charles Frémont's expeditions from 1842 to 1844, included on his epic Map Of An Exploring Expedition To The Rocky Mountains (1845). Important features include 'Great Salt Lake', in the region where Brigham Young would lead Mormon pioneers in 1847. Also noted are great new details with respect to the Platte, Colorado and Snake Rivers and in the Cascade and Sierra Nevada Mountains. While much more remained to be discovered, Frémont succeeded in laying out the basic parameters of the interior Southwest.
In describing the 1846 Third Edition, Rumsey notes:
This 1846 edition has updated the western cartography to include Fremont's route and topography in California and the Rocky Mountains. Interestingly, Lake Tahoe is labeled Flag Lake, a name we have never seen before. . . Also included is a large inset in the lower left of the map, 'Map of the Roads &c. from Vera Cruz and Alvarado to Mexico City'. This corridor details the region where the decisive action of the war would be fought. General Winfield Scott's successful campaign to capture Mexico City, lasted from April 25, 1846, to February 2, 1848. Above is a table of distances between key points in Mexico.
This Fourth Edition adds an inset map of the Harbor of Vera Cruz. While Wheat also reports changes in Northern New Mexico between the third and fourth editions.
The Mexican American war ended with a resounding U.S. victory upon the signing of the Treaty of Guadalupe Hidalgo on February 2, 1848. Mexico officially ceded Texas and the Southwest, although due to the ambiguities in the known geography around the Gila River, the border would later be further amended by the Gadsden Purchase (1853).
Henry Schenk Tanner (1786-1858) was during the time that this was issued, the most respected and successful American map publisher, responsible for such grand projects as A New American Atlas (1819-23) and a sequence of wall maps of the Unites States.
The "Fourth Edition" of Tanner's Mexico map sequence is one of the truly great maps of the American Southwest, and is certainly the finest and most influential general map of the theatre of the Mexican-American War.