Fort Union National Monument

Park Preserved 19th-century trading post on the Santa Fe Trail

On the high plains of New Mexico, Fort Union preserves 19th‑century military ruins that supplied the Santa Fe Trail; visitors follow trails, see interpretive exhibits and view artifacts.

Main image

Fort Union National Monument preserves the remains of a 19th-century U.S. Army fort and associated facilities in northeastern New Mexico. The site interprets military and commercial activity along the Santa Fe Trail during the 1800s.

Visitors can follow trails past adobe ruin foundations, reconstructed structures and a visitor center with exhibits on the fort’s role as a supply depot and military post. The monument covers an archaeological footprint with visible building outlines and informational signage.

The fort was established in the mid-19th century as a military post and supply depot supporting operations along the Santa Fe Trail and regional frontier duties; it was occupied through the late 19th century. Over time the post was abandoned and the ruins have been stabilized and interpreted by the National Park Service.

Fort Union lies in a high plain near Watrous and Las Vegas, New Mexico, in gently rolling grassland; the site is accessible from Interstate 25 and is roughly 60-80 miles northeast of Santa Fe depending on route.

  • Interpretation: Interpretive trails and a visitor center explain the site's role on the Santa Fe Trail and its function as a 19th-century army supply depot; guided walks pass reconstructed buildings and archaeological remains.
  • Operational period: The fort was active from the early 1850s through to the late 19th century and played a logistic role in military operations and protection of commerce on the Santa Fe Trail.
Fort Union National Monument
35.9070, -105.0145

Tips for Visiting Fort Union National Monument #

  • Plan an early-morning visit to avoid afternoon heat and strong plains winds and to see the ruins in cooler, calmer conditions.
  • Stop in at the visitor center on arrival for maps and the short interpretive trail route-the monument is compact but spread out and the center orients you to the best viewpoints and signage.
  • If possible visit on a weekday or outside peak summer months to avoid larger tour groups that tend to arrive midday; the site feels far quieter in the shoulder seasons.

Best Time to Visit Fort Union National Monument #

Visit in late spring or early fall for the most comfortable weather and reliable access; avoid the hottest monsoon afternoons and winter snow.

Spring
Apr-May · 5-20°C
Mild days ideal for walking the exposed ruins; generally comfortable conditions and good visibility.
Summer (monsoon season)
Jun-Aug · 15-30°C
Hot daytime temperatures with possible afternoon thunderstorms during the Southwest monsoon-bring sun protection and water, and expect brief storm-related disruptions.
Fall
Sep-Oct · 5-22°C
Cooler, pleasant weather for exploring the site with generally lower chance of storms and comfortable hiking conditions.
Winter
Nov-Mar · -10-8°C
Cold conditions with possible snow and strong winds; trails and access can be affected-check conditions before travel.

Weather & Climate near Fort Union National Monument #

Climate

Fort Union National Monument's climate is classified as Cold Semi-Arid - Cold Semi-Arid climate with warm summers (peaking in July) and freezing winters (coldest in January). Temperatures range from -9°C to 29°C. Semi-arid with limited rainfall.

Temperature & Rainfall
Temperature Range
29°
Warmest Month
-9°
Coldest Month
Monthly Conditions

January

January is the coldest month with highs of 9°C and lows of -9°C. The driest month with just 13 mm.

Comfort

Feels Like Freezing
C
Temperature
-9°

Weather

13 mm
Rainfall
4.3 m/s
Wind
Light Breeze

February

February is cold with highs of 11°C and lows of -8°C. Light rainfall.

Comfort

Feels Like Cold
C
Temperature
-8° 11°

Weather

14 mm
Rainfall
4.5 m/s
Wind
Light Breeze

March

March is cold with highs of 14°C and lows of -5°C. Light rainfall.

Comfort

Feels Like Cold
C
Temperature
-5° 14°

Weather

20 mm
Rainfall
5.0 m/s
Wind
Light Breeze

April

April is cold with highs of 18°C and lows of -2°C. Light rainfall.

Comfort

Feels Like Cold
C
Temperature
-2° 18°

Weather

21 mm
Rainfall
5.3 m/s
Wind
Light Breeze

May

May is cool with highs of 23°C and lows of 3°C. Moderate rainfall (45 mm).

Comfort

13°
Feels Like Cool
13°C
Temperature
23°

Weather

45 mm
Rainfall
5.0 m/s
Wind
Light Breeze

June

June is cool with highs of 28°C and lows of 8°C. Moderate rainfall (50 mm).

Comfort

18°
Feels Like Cool
18°C
Temperature
28°

Weather

50 mm
Rainfall
4.6 m/s
Wind
Light Breeze

July

July is the warmest month with highs of 29°C and lows of 11°C. Regular rainfall (80 mm).

Comfort

20°
Feels Like Mild
20°C
Temperature
11° 29°

Weather

80 mm
Rainfall
3.9 m/s
Wind
Light Breeze

August

August is mild with highs of 28°C and lows of 10°C. The wettest month with 85 mm of rain.

Comfort

19°
Feels Like Mild
19°C
Temperature
10° 28°

Weather

85 mm
Rainfall
3.7 m/s
Wind
Light Breeze

September

September is cool with highs of 25°C and lows of 6°C. Moderate rainfall (54 mm).

Comfort

16°
Feels Like Cool
16°C
Temperature
25°

Weather

54 mm
Rainfall
4.0 m/s
Wind
Light Breeze

October

October is cool with highs of 20°C and lows of 0°C. Light rainfall.

Comfort

10°
Feels Like Cool
10°C
Temperature
20°

Weather

28 mm
Rainfall
4.3 m/s
Wind
Light Breeze

November

November is cold with highs of 14°C and lows of -5°C. Light rainfall.

Comfort

Feels Like Cold
C
Temperature
-5° 14°

Weather

19 mm
Rainfall
4.3 m/s
Wind
Light Breeze

December

December is cold with highs of 10°C and lows of -9°C. Light rainfall.

Comfort

Feels Like Cold
C
Temperature
-9° 10°

Weather

16 mm
Rainfall
4.3 m/s
Wind
Light Breeze

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