Petrified Forest of Sarmiento: A 65-Million-Year-Old Forest

The Petrified Forest of Sarmiento lies 30 km south of Sarmiento town, roughly 150 km west of Comodoro Rivadavia, along a gravel spur off Ruta Nacional 26 in Chubut Province. The protected area covers 1,832 hectares of Patagonian steppe, and its stone trunks date back about 65 million years — you can walk the interpretive trail in an hour and drive back to Comodoro the same day.

Getting There and Planning Your Visit

Driving from Comodoro Rivadavia

The most direct route from Comodoro Rivadavia to the fossil site is Ruta Nacional 26 west to Sarmiento, then Ruta Provincial 23/26 south onto the marked gravel access road. Plan on about two hours of driving each way. The last stretch is unpaved and conditions change with weather; local tourism authorities periodically issue advisories asking drivers to keep speeds low, and the road is generally passable for standard cars when dry. Fill your tank in Sarmiento — the access road has no services at all.

No Car? Book a Remis in Sarmiento

Public transport does not reach the monument. Travelers without a vehicle typically hire a remis from Sarmiento, which charges for the return trip including roughly an hour of waiting time. A private transfer from Comodoro Rivadavia is another option at about 150 km one way, but confirm the driver will wait at the site — otherwise you're stranded in the badlands.

Opening Hours and Entry Fees

The visitor center and trail operate roughly 8:00 to 20:00, though hours shift by season and the site has been known to close without notice after heavy wind or rain. Entry has been free on designated open days (such as the March 21 International Day of Forests, when guards guide visitors at no cost), and some sources report an entrance fee of a few hundred pesos per foreign adult. Fees are subject to change — check with the Sarmiento tourism office for current rates before you drive out.

What You'll See on the Trail

The Stone Trunks

The heart of the experience is a self-guided interpretive trail of roughly 1 to 2 km that loops past dozens of exposed petrified logs. These are permineralized Araucariaceae and Podocarpaceae trunks — the ancestors of today's monkey puzzle trees — and many lie where they fell, some split into perfect stone discs, others hollowed into giant rings. Silica replaced the wood cell by cell after volcanic ash buried the forest in the Paleocene. Run your hand along a polished cross-section and you can still read growth rings 65 million years old.

Colored Badlands and the Visitor Center

The surrounding eroded clay hills are banded in grey, red, ochre and pale green — striking against the beige steppe. A small visitor center displays paleontological finds from the area, including dinosaur and marine fish fossils recovered from the surrounding cañadones, and explains how the Andes' rise blocked Pacific moisture and turned a warm, wet forest into desert. Guided visits in English can be arranged; otherwise, the self-guided route works fine.

How Long to Allow

Two to three hours covers the trail, the visitor center and photography stops comfortably. Photographers should budget more: the low morning and late afternoon light on the striped hills is the reason to come, and midday sun flattens the colors. I'd skip the site entirely on a day of strong sustained wind — the exposed plateau offers no shelter, and blowing grit makes the walk unpleasant.

Best Time to Visit and Rules to Respect

Seasons and Conditions

September through April is the practical window. Patagonian spring and summer bring long daylight, but wind is a constant companion — 40 km/h gusts are ordinary. Winter access is possible but the gravel road and cold make it a gamble. Payload essentials: sturdy closed shoes (the trail surface is loose scree), at least 2 liters of water per person, sun protection, and a windproof layer. Temperatures on the plateau can swing widely in a single afternoon.

Protecting the Fossils

This is a provincial natural monument, created in 1970 and administered under a management plan, not a roadside curiosity. Rules are simple and enforced: do not remove wood, fossils, rocks or plants; stay on the marked trail; no climbing on the trunks. Collecting even a fist-sized fragment is illegal and depletes a site that is one of the largest concentrations of petrified wood in Patagonia. Rangers (guardafaunas) are on site on busy days and will answer questions.

Pairing It With Other Stops

Sarmiento town sits between Lakes Musters and Colhué Huapi, both worth a detour for birdlife and steppe views. The town also has full-size dinosaur replicas and a paleontological museum that make a good half-day complement. Comodoro Rivadavia's airport is the usual arrival point; the fossil forest works well as a first or last stop on a Chubut loop that continues toward Río Mayo and the Andean foothills.

Frequently Asked Questions

How far is the Petrified Forest of Sarmiento from Comodoro Rivadavia?

About 150 km, or roughly two hours by car via Ruta Nacional 26. The final 30 km south of Sarmiento is a gravel road with no fuel or services.

Do I need a guide to visit?

The trail is self-guided and signed, but a local guide adds real value by explaining the permineralization process and pointing out fossils you'd otherwise walk past. Guided visits in English can be booked through Sarmiento operators.

How much does entry cost?

The site has charged a modest entrance fee of a few hundred pesos per adult, with free-entry days on environmental holidays. Rates change — confirm the current price at the Sarmiento tourism office before driving out.

Can I visit in winter?

Cold, wind and uncertain gravel-road conditions make winter a poor bet. Aim for September to April, and pack a windproof jacket even then.