New Mexico: Fort Union National Monument

scenic ruins
Scenic Ruins of the site’s third, and final, fort are all that remain today of the grand complex

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First established in 1851 in the Mora Valley in northeastern New Mexico, Fort Union was the main guardian of the Santa Fe Trail, one of the most important overland trade routes serving North America since the early 1820s. The trail itself was originally established approximately 2,000 years ago by American Indians and, during the 19th Century, became a complex web of international business, social ties, tariffs and laws, which allowed millions of dollars of commercial traffic to flow between Independence, Missouri and Santa Fe, New Mexico. Fort Union, situated in land used by plains and pueblo Indians, sat at the junction of the two main branches of the Santa Fe Trail to protect travelers, commerce, and mail routes from increasingly frequent Indian raids. Through the Santa Fe Trail, Fort Union, and the United States Army, Anglo-American culture penetrated the Hispanic and Indian cultures of the region. 

Today, Fort Union National Monument reflects the fort’s evolution from the 1850s through the Civil War and into the late 1880s. Visitors can experience the site’s cultural ties and military history by viewing the ruins of three separate forts and see some of the best-preserved wagon ruts of the Santa Fe Trail--all in a prairie setting that evokes the time when Fort Union played an important role in the settlement of the American West.


Fort Union: An Evolution of Protection

In 1821, Mexico gained its independence from Spanish rule. The Santa Fe Trail soon became a great gateway to the West. The trail made possible the transporting and trading of goods such as furs, woolens, cottons, silks, china cups, whiskey, combs, flatware, jewelry, dry goods, and hardware. It was also an avenue for the exchange of cultural practices and traditions, as many different peoples met and did business with one another. Americans and New Mexicans, settlers and traders from the eastern part of the United States and beyond, and newly independent Mexicans converged with American Indian tribes including Comanche, Kiowa, southern bands of Cheyenne, Arapaho, Plains Apache, Osage, Kansas (Kaw), Jicarilla Apache, Ute, and Pueblo Indians. During the early years of the Santa Fe Trail, most, but not all, encounters between travelers and the Indians were peaceful.

With the United States’ annexation of northern Mexico in 1848 as a result of the Treaty of Guadalupe Hidalgo, traffic along the Santa Fe Trail increased exponentially. As the trail’s popularity grew, relations with American Indians began to deteriorate. The great influx of people along the Santa Fe Trail disrupted their way of life and negatively impacted the environment, prompting many tribes to retaliate. With Indian raids becoming a frequent occurrence, the United States government responded by increasing military presence along the route and establishing Fort Union in 1851 (and later, Fort Larned, another unit of the National Park System featured in this travel itinerary).

Lt. Col. Edwin V. Sumner, the commander of the Military Department of New Mexico, established Fort Union at the junction of the Mountain and Cimarron branches of the Santa Fe Trail to protect the region. During the first few years, Fort Union's mounted troops patrolled the trail and provided escorts for mail stages. The soldiers lived in poor conditions at the shoddily constructed first Fort Union. Made of unseasoned, un-hewn and un-barked wood, the fort’s small, low buildings suffered from extensive rot and pest infestation. Even the fort’s hospital was dark, damp, and under constant threat of a roof collapse.

The start of the Civil War brought changes to Fort Union on a grand scale, as the Confederacy plotted an invasion aimed at capturing the western portion of the Santa Fe Trail and the entirety of the Southwest, which included the highly prized silver and gold fields of Colorado and California. This potential Confederate threat of diverting much needed goods and mineral wealth away from the Union prompted the Federal Government to build a new Fort Union in the valley to the east of the first structures. The second fort began to take shape in 1861 as a massive, bastioned earthwork with parapets in the shape of an eight-pointed star. Each parapet supported firing platforms and artillery emplacements, and within each star point were barracks, storehouses and officers’ quarters. Despite the improved defenses, living conditions for the soldiers remained largely unchanged. Within the earthen outer walls, buildings of the second fort were made of un-barked pine logs that quickly rotted and housed nesting insects, promoting disease and illness.

Work on the second Fort Union continued as Confederate forces neared, capturing the capital of New Mexico, Santa Fe. With their immediate sights set on Denver, Colorado, Fort Union was the only major military obstacle in the Confederates’ path. Union soldiers from Fort Union, comprised of native Hispano volunteers from New Mexico and regiments from Colorado, quickly joined forces and headed south to meet the Confederate Army nineteen miles outside of Santa Fe at Glorieta. The Battle of Glorieta Pass, March 26-28, 1862, was the decisive battle in the New Mexico Campaign during the Civil War in the Western territories. The Union win squelched the "grand design for the Confederacy in the West" and eliminated the Confederate threat to the region. After the Battle of Glorieta, Union forces continued the campaign against American Indians in the Southwest Territory.

Today, the second Fort Union is the sole surviving earthen star fort erected west of the Mississippi River. It is the most intact Civil War-era, bastioned, earthen fort remaining anywhere within the United States.

In 1863, with New Mexico securely in Union hands, the large defensive fort was no longer necessary. Work began on the third, and most substantial, of the fortifications at the Fort Union site, which took six years to complete. The new fort included the Post of Fort Union, the Fort Union Quartermaster Depot, and the Fort Union Ordnance Depot and was the largest ever constructed in the American Southwest. The large territorial style buildings of adobe brick coated in kiln-fired plaster set on stone foundations were of native materials better equipped to handle weather conditions, unlike the earlier forts. Tools, nails, properly dressed lumber, window glass, and red- fired bricks all came via the Santa Fe Trail from as far away as Santa Fe and Missouri.

Although it still functioned to protect travelers along the Santa Fe Trail, the new fort primarily responded to the needs of the area’s trade and military supply concerns. The two depots served as supply bases for large portions of the Southwest’s military outposts as the Indian Wars continued. The Quartermaster Depot was the largest and most elaborately staffed trade post in the region. The fort had an array of structures and amenities, from a teaching hospital to a chapel, classrooms, warehouses, mechanics, and stables.

Fort Union’s role of protecting commerce along the Santé Fe Tail continued until the arrival of the Atchison, Topeka, and Santa Fe Railroad in 1879, which slowly put an end to the Santa Fe Trail. Once traffic dwindled on the trail, the fort continued its policy of “pacifying” and relocating local American Indian peoples onto designated reservations. At Fort Union, between 1876- 1881, and then again from 1886-1887, this military duty fell upon the Ninth Cavalry. Comprised of African-American soldiers and commonly referred to as “Buffalo Soldiers”, the members of the Ninth Cavalry distinguished themselves in service at Fort Union and throughout other military outposts in the Southwest. Finally, in 1891, a year after the traditional closing of the frontier and conclusion of the Indian Wars, the military officially abandoned Fort Union.

Today, Fort Union National Monument serves as a reminder of the fort’s history and the vital role it played in the development of the distinct cultural character of the American Southwest and the settlement of the American West. Visitors to Fort Union National Monument can experience the entire history of the site and its three consecutive forts. Although no aboveground ruins of the first fort remain,interpretive programming, special events, and guided tours at the first fort site help explain the fort. The earthworks of the second fort and the ruins of the third still stand as dramatic features on the landscape. A 1.6-mile and a 0.5 mile self-guided trail interpret the ruins for visitors. All interpretive trails are fully accessible by wheelchair. The largest and best-preserved network of wagon ruts from the Santa Fe Trail is visible near the third fort’s ruins.

The park offers special family and children friendly programs. A digital copy of the National Park Service’s Junior Rangers booklet for the park can be found here or in hardcopy at the park’s visitor center. For more information on various events young people will enjoy, check out the park’s website here.

Fort Union National Monument, a unit of the National Park System, is located in the Mora Valley in northeastern New Mexico at the western edge of the Great Plains, eight miles from Watrous, NM. The park is easily accessible via New Mexico Highway 161, Exit 366, on Interstate 25. The monument is open daily except on Thanksgiving, Christmas and New Years Day. Winter hours from Labor Day to Memorial Day are 8:00am to 4:00pm. Summer Hours from Memorial Day to Labor Day are 8:00am to 6:00pm. For more information, visit the National Park Service Fort Union National Monument website or call 505-425-8025.

Click here for the National Register of Historic Places file: text. This travel itinerary series also includes the Santa Fe Trail and Fort Larned.

Last updated: August 4, 2017