The Story:
At the conclusion of the Mexican-American War, the Treaty of Guadalupe Hidalgo dramatically added new lands to the United States, with Mexico ceding 55% of its territory -- including present-day Arizona, California, New Mexico, Texas, and parts of Colorado, Nevada and Utah -- in exchange for fifteen million dollars in compensation. America's swift and successful completion of the war was greatly aided by a mostly forgotten group of volunteers known as Doniphan's Thousand.

In the spring of 1846, the war between the U.S. and Mexico was in full swing when Alexander W. Doniphan joined hundreds of his fellow Missourians and enlisted to fight in the war. Up and down the Missouri River volunteers from each Missouri county joined up and were eventually mustered at Fort Leavenworth as the First Regiment Missouri Mounted Volunteers. Over the next year, Doniphan would lead this small ragtag-looking unit numbering fewer than 1,000 men -- most with little or no military experience -- on an astonishing campaign through Mexico.

A brief aside:
Alexander W. Doniphan had joined the Clay County Company as a private, but in the selection of officers he was elected Colonel of the Regiment. Before enlisting Doniphan was a lawyer and a commander in the state militia. A decade earlier he had saved the life of Joseph Smith -- the leader of the Church of Jesus Christ of Latter Day Saints. To quell civil unrest sparked by Mormon settlements in northwest Missouri, Governor Lilburn W. Boggs ordered state troops under the command of General Samuel D. Lucas to exterminate the Mormons. Smith and his Mormons eventually surrendered to Lucas and were to be executed, but Doniphan stood in opposition and promised General Lucas that he would see the General prosecuted for murder if he went ahead with the executions. The General held off and the Mormons eventually escaped and fled the state.

Back to our story:
The first objective for the regiment was the Mexican city of Santa Fe. They marched out of Fort Leavenworth on June 26, 1846 -- crossing the Kansas River and joining the Santa Fe Trail. The regiment crossed into Mexican territory on the 29th of July and Santa Fe was entered unopposed on the 18th of August, 1846 -- capturing New Mexico without shedding a drop of American blood.

The autumn months were spent in New Mexico skirmishing with the Navajo and eventually reaching a peace with them. As winter approached the Regiment was given orders to join up with General Wool's army in Chihuahua.

Doniphan set out for Chihuahua, 300 miles away, with 856 fighting men. Not far along the way, on Christmas Day, they routed the Mexicans in a farcical engagement at the Brazito River and occupied El Paso. They then pushed on to a point 15 miles north of Chihuahua where they met the Mexican Army in the Battle of Sacramento (Feb. 28, 1847). In one of the most remarkable battles ever fought by the American military, an army of five thousand Mexicans was attacked and destroyed by an army of volunteers less than a thousand strong -- and the Missourians had but four men killed and eight wounded.

Chihuahua was taken the next day, but General Wool was not there as planned. General Wool and his men had run into some difficulty in Saltillo. The Regiment received orders to go to Wool's aid, so Doniphan began the 600 mile march to Saltillo, which they reached late in May.

Upon arrival they found the situation under control and their terms of enlistment completed. After receiving a commendation from Zachary Taylor, Doniphan's Thousand went down the Rio Grande, sailed to New Orleans, and marched home to Missouri. The expedition came to an end one year after it began covering some 5,000 miles -- 3,600 of them on foot. It was conducted with minimal loss under adverse circumstances, mostly within enemy territory. They had no supply lines and simply lived off the land.

Alexander Doniphan, who returned to law practice in Richmond, Mo., opposed secession and favored neutrality for Missouri in the war between the states. Although offered a high command by the Union, he took no active part in the American Civil War.

http://skyways.lib.ks.us/genweb/archives/1918ks/v1/ch8p4.html
http://www.bartleby.com/65/do/Doniphan.html