
Blue skies and billowing clouds frequently add to the incredible viewshed that surrounds the monument grounds.
Photo: Ron Harvey - Fort Union National Monument
Exposed to the wind, within a sweeping valley of short grass prairie, and along the eroded Santa Fe Trail, lie the adobe walled ruins of the largest 19th century military fort in the region. From 1851 to 1891, Fort Union functioned as an agent of change, desired or not, in the New Mexico Territory and throughout the Southwest.
Fort Union National Monument is located in the Northeastern portion of the state of New Mexico. 8 miles off of Interstate I-25 on State Highway NM 161. New Mexico: From Albuquerque (156 miles), Santa Fe (94 miles) or Las Vegas, NM (28 miles) take I-25 North, exit 366 at Watrous, 8 miles on NM 161. Colorado: From Denver (313 miles), Colorado Springs (243 miles) or Raton (95 miles) take I-25 South, exit 366 at Watrous, 8 miles on NM 161.
Get directions →Fort Union is situated at 6,760 feet above sea level. Daytime temperatures between June and September may exceed 90 degrees Fahrenheit. Winter temperatures often drop below 32 degrees Fahrenheit. Temperatures may vary within 50 degrees in a 24-hour period. During the winter, it is not uncommon for the temperatures to drop below 0°F (-18°C.) During the summer, expect high temperatures, intense sunlight and extremely low humidity.
National Park Service’s Pueblo Parks Group Implements Stage II Fire Restrictions
National Park Service’s Pueblo Parks Group Implements Stage II Fire Restrictions

“Fashions & Pastimes” Program June 19-21
Fort Union National Monument will host “Fort Fashions & Pastimes” programs from June 19-21, 2026. The free programs will feature 1800s clothing styles, leisure activities, and how both related to economics and social structures of the time.
Fort Union Days - 2026
The event will feature an 1800s military encampment, living historians portraying soldier and civilian life, and historic weapon and uniform presentations highlighting the period of the 1850s to 1890s.