Chicken Creek Nature Loop, Fossil Butte Nat'l Monument, Wyoming

Distance: 1.5 miles (2.4 km)

Difficulty: Easy

Elevation: 7,500-7,800 feet (2285 - 2375 m)

Time of Year: Anytime (will be cold and icy in winter)

Fossil Butte National Monument, in southwestern Wyoming represents perhaps the world's greatest and best preserved fish fossils. The was the site of a huge and very stable lake some 50 million years ago. What is today a landscape of cold-desert sagebrush, was once a subtropical landscape of palms, warm weather trees, crocodiles, and fish only found in regions like Southeast Asia today.

50 million year old bat fossil showing they were essentially in their modern form by that point already

While remote, if you are ever traveling down I-80 through southern Wyoming or north to Yellowstone, it is worth the side-trip to see this amazing site. The visitor center is full of these fossils and has a great video showing how they extract these fossils of the laminate rocks on the butte.

Small fish here all died when oxygen conditions changed rapidly, then were buried by sediment

A 4-foot wide palm frond

In addition, there is a nice hiking trail that leads you through the sagebrush into an aspen glade in a drainage and up to an active quarry site where paleontologists are extracting fish fossils to this day. The Chicken Creek Nature Trail begins two miles up the road from the visitor center. The trail starts up along a sage brush slope along the sides of the aspen stand. At this elevation and in this dry landscape, the only trees are spindly aspens in the wettest drainages where seeps and springs occur. 

Beginning of the Chicken Creek Nature Loop

The trail climbs 300 feet up to the base of the exposed rock on the butte. At the top of the trail, there is a side trail. If the park is actively quarrying, the gate is open and you can go up and talk to the rangers or scientists doing the work. Otherwise, the gate will be closed to the public.

A volunteer working on extracting fossils

A view from the quarry site

From this high point, the view across the landscape of southwestern Wyoming is quite expansive. The trail then heads into and across the aspen stand into a lush green understory almost unimaginable in otherwise desolate Wyoming. Do be aware of mosquitoes who lurk in these woods, as there are a number of small stagnant pools in this drainage for them to breed in.

In the aspen stand

The trail will then descend down the slope on the otherside of the stand to the dirt road, which you walk down a few hundred feet more back to the parking area. You can also climb up the dirt road to the 8200 foot ridge summit for even more expansive views of the landscape.

As Fossil Butte was 50 million years ago