Chimney Rock National Monument

Chimney Rock National Monument is located near Pagosa Springs and is one of Colorado’s newer National Monuments, founded in 2012. Chimney Rock is best known for an archeological site that is towered over by two big geologic features.


Major Lunar Standstill season at Chimney Rock National Monument

Chimney Rock National Monument (located near Pagosa Springs Colorado) has been an enigma to archeologists for decades. The Monument consists of an archeological site (constructed by the ancestral puebloan people that used to inhabit the four corners region) and two geologic features (two pinnacles that make up the ‘chimney rock’ that tower over the archeological site). The geologic features were thought to be used as seasonal indicators by the ancestral puebloans, denoting the position of the sun, much like stonehenge was used to tell solstice/equinox. However, it never added up, the sun would never rise between the two pillars.


While studying the site archeologist looked at the tree rings of the wood used by the ancestral puebloans to build the structures. Comparing the tree rings of trees that are still standing to the ones used in the structures, archaeologists could tell when the wood was harvested and get an idea of when it was built. They noticed that building seemed to happen in 18 year periods showing that activity at chimney rock was on a periodic 18 year cycle. They took this finding to an astronomer and asked ‘what (if any) phenomenon happens in the sky every 18 years!?’ and the astronomer knew right away that it was a cycle of the moon not the sun, namely the ‘Major Lunar Standstill’.


Basically Major Lunar Standstill is an 18 year cycle of the moon where the moon moves to the northernmost position it will be in the sky. I have a blog post explaining it more here https://www.astrotours.org/post/major-lunar-standstill. In short; this means for the next ~3 years there will be plenty of opportunities to see the moon rise between the Chimney Rocks but after the last one occurs in September 2026 it won’t be seen again for another 18 years.


Date and time when the full moon can be seen rising between the spires at Chimney Rock National Monument

Thu 05 Jan, 2023 | 3:56 pm

Tue 28 Nov, 2023 | 5:50 pm

Mon 25 Dec, 2023 | 3:41 pm

Tue 26 Dec, 2023| 4:34 pm

Tue 23 Jan, 2024| 3:23 pm

Sat 14 Dec, 2024 | 4:06 pm

Sun 15 Dec, 2024 | 5:06 pm

Sat I I Jan, 2025 | 2:50 pm

Sun 12 Jan, 2025 | 3:53 pm

Fri 05 Dec, 2025 | 5:30 pm

Thu 01 Jan, 2026 | 3:06 pm

Fri 02 Jan, 2026| 4:14 pm

Wed 25 Nov, 2026 | 5:49 pm

Wed 23 Dec, 2026| 4:33 pm

This undiscovered gem is an intimate, off-the-beaten-path archaeological site located at the southern edge of the San Juan Mountains  in Southwestern Colorado. Archaeological ruins and artifacts, abundant wildlife, and its setting in the breathtaking San Juan National Forest make Chimney Rock a must-see.  Chimney Rock covers seven square miles and preserves 200 ancient homes and ceremonial buildings, some of which have been excavated for viewing and exploration. Chimney Rock is the highest in elevation of all the Chacoan sites, at about 7,000 feet above sea level.