- Where
- North-east San Juan Province
bordering Talampaya, La Rioja - Coordinates
- 30.0667° S
68.0000° W - Rocks
- Late Triassic, about 231–226 million years old
(Wikipedia) - Area
- About 60,000 hectares
provincial park since 1971 - Status
- UNESCO World Heritage, 2000
with Talampaya National Park - The circuit
- About 40 km, five stops, about 3 hours
guided (park’s official site) - Best visited
- Year-round; early departures miss the afternoon wind
- Advisory
- Argentina Level 1
The ground was pale grey and bare, and behind it rose a wall of red cliffs, very tall, with a wind coming off them in the afternoon as if someone had left a door open. Out on the flat stood a stone on a thin stalk, like something that had grown overnight and decided to stay. A guanaco watched us all from a ridge, unimpressed by any of it.
The short answer
Ischigualasto Provincial Park is a protected area in the north-east of San Juan Province, in north-western Argentina, bordering Talampaya National Park in the province of La Rioja to the north; the two parks share the same geological formation. Wikipedia gives the park’s area as 60,370 hectares and its establishment as 3 November 1971; San Juan’s tourism body gives about 62,000 hectares. It lies at about 1,300 metres, in very dry country with desert scrub and cacti. UNESCO inscribed Ischigualasto and Talampaya together as a World Heritage Site in 2000. The park is also called Valle de la Luna, the Valley of the Moon, a name Wikipedia traces to a 1943 publication of the Automóvil Club Argentino; it is not the Valle de la Luna in northern Chile’s Atacama Desert, which is a different valley in a different country.
Why it's worth knowing
Where the dinosaurs begin. UNESCO describes the two parks as holding the most complete continental fossil record known from the Triassic Period, with a sequence of formations covering the whole of it. The Ischigualasto Formation itself dates, by Wikipedia’s figures, to between about 231.4 and 225.9 million years ago, when this was a river floodplain with strongly seasonal rain and trees more than 40 metres tall. Most of the four-limbed animals found here are not dinosaurs: plant-eating rhynchosaurs and cynodonts dominate the finds, and Wikipedia reports that dinosaurs make up only about 11 per cent of them. Those few are among the earliest known. Herrerasaurus is the commonest; Eoraptor lunensis, found in 1991 by Ricardo Martínez of the University of San Juan with Paul Sereno, and named in 1993, means “dawn plunderer from the Valley of the Moon”.
Colours in layers. The Ischigualasto Formation is pale, and Wikipedia notes that its colour contrasts sharply with the formations below and above it: the Los Rastros, mostly green mudstone, and the Los Colorados, mostly red sandstone. Tall red cliffs, known as the Barrancas Coloradas, stand above the pale valley floor, and the softer beds of the floor have been worn into the free-standing shapes the park is known for.
The field notes
The named stones
Wikipedia’s captions name three of the wind-cut formations: the Submarine, a long ledge of sandstone with a raised “conning tower”; the Sphinx; and the Mushroom, El Hongo, a broad cap on a narrow stem. The park’s official site lists the traditional circuit’s stops among them, with the Valle Pintado at its start and the Cancha de Bochas, the “bowls court”, where the fossil-rich beds come to the surface. The park also has the Dr. William Sill Site Museum.
Wind, heat and the guided circuit
Wikipedia records temperatures from −10 °C to 45 °C and a steady southerly wind of 20 to 40 km/h from midday into the evening, sometimes with the hot, dry zonda. The park keeps its main route to a guided visit: its official site describes the traditional circuit as about 40 kilometres with five stops, taking about three hours, guided by authorised park staff, with group departures through the day. It also lists a full-moon circuit, a mountain-bike circuit and a walk in the Quebrada de la Peña.
What the name means
The sources differ. Wikipedia gives Ischigualasto as coming from the extinct Cacán language of the people the Spanish called the Diaguita, meaning “place where the moon alights”; it also records a Diaguita reading, “dead land”, and a proposal of Huarpe roots. The first scientific description of the valley’s fossils dates from 1930, and Wikipedia records that the Harvard palaeontologist Alfred Sherwood Romer called the beds he found there in 1958 “extraordinary”.
El Submarino, a wind-cut sandstone ledge, December 2014.
Photograph: Levofloxacino · CC BY-SA 4.0 · cropped
Round stone concretions scattered across the Cancha de Bochas, February 2006.
Photograph: Ccarosio · CC BY-SA 4.0 · cropped
A guanaco in the grey badlands, August 2017.
Photograph: Coticuenca · CC BY-SA 4.0 · cropped
El Hongo: a capped column of sandstone, January 2013.
Photograph: Fernando de Gorocica · El Hongo · CC BY-SA 3.0 · cropped
- Join the first group out, while the air is still and the shadows are long.
- Visit the little museum first, so you know what to look for, and again at the end to see what you missed.
- Name the stone shapes before the guide does. I had a ship, a sleeping dog and a teapot written down; the guide had other names, and now the list has both.
- Keep to the track at every stop. The pale ground takes a footprint easily and gives it back slowly.
- Ask the guide which stone has changed most since they began the work. Then look at that one longer than the rest.
El Hongo, the Mushroom. A column of pale sandstone on the valley floor, a broad cap balanced on a narrow stem, worn into shape by the wind and the rare rain, with the red cliffs of the Barrancas Coloradas behind it. Wikipedia names it among the park’s wind-cut formations, and it is seen from the guided circuit.
Tally, in the marginWho taught it to stand like that, all that cap on one thin stalk? I walked round it twice, and only on the third time round did I catch myself tiptoeing.
Getting there
How to get there. By road. San Juan’s tourism body puts the park 330 kilometres from the city of San Juan and 75 kilometres from San Agustín del Valle Fértil, the nearest town. The park’s official site gives the main approaches: National Route 150, paved, from Jáchal in the west or from Patquía in La Rioja, and Provincial Route 510 north through the Valle Fértil department. Inside, visits follow the guided circuit of about 40 kilometres, with group departures through the day; the official site lists departures at 8, 10, 12, 14, 16 and 17 hours, with groups travelling in vehicles approved for the circuit, or in the park’s own, with an official guide.
When to go. Year-round. Take an early departure: the wind gets up after midday, and summer afternoons are fierce. The park also runs a full-moon circuit.
What to arrange ahead. A car or a tour from San Juan or Valle Fértil, and a place on the circuit; the park’s official site takes bookings by circuit. Check its current timetable and fees before setting out. Bring water, sun protection and a warm layer for the wind.
Safety. The State Department has Argentina at Level 1, exercise normal precautions (10 July 2026). It notes a CDC Level 1 health notice for Andes virus (hantavirus) in the region, with the risk for most travellers extremely low, and crime and violence linked to drug trafficking in Rosario, Santa Fe province, far from San Juan. The hazards here are the place’s own: heat, sun and wind.
Mark this place
Common questions
Where is Ischigualasto?
Ischigualasto Provincial Park is in north-eastern San Juan Province, Argentina, bordering Talampaya National Park in La Rioja. San Juan’s tourism body puts Ischigualasto 330 kilometres from the city of San Juan and 75 kilometres from San Agustín del Valle Fértil.
Is Ischigualasto the same as the Valle de la Luna in Chile?
No. Ischigualasto, in San Juan Province, Argentina, is nicknamed Valle de la Luna, a name Wikipedia traces to a 1943 Automóvil Club Argentino publication. Chile’s Valle de la Luna, in the Atacama Desert, is a different valley in a different country.
What dinosaurs were found at Ischigualasto?
Ischigualasto’s rocks hold some of the earliest known dinosaurs. Herrerasaurus is the most numerous, and Eoraptor lunensis was found there in 1991 by Ricardo Martínez and Paul Sereno. Wikipedia notes that dinosaurs are only about 11 per cent of the four-limbed animals found; plant-eating rhynchosaurs and cynodonts dominate.
How old are the rocks at Ischigualasto?
The Ischigualasto Formation is Late Triassic: Wikipedia gives its fossil-bearing beds in the park as about 231.4 to 225.9 million years old. UNESCO describes Ischigualasto and Talampaya together as holding the most complete continental fossil record known from the Triassic Period.
How do you visit Ischigualasto?
On a guided circuit. The park’s official site describes Ischigualasto’s traditional circuit as about 40 kilometres with five stops, taking about three hours, with an official guide and group departures through the day. It also offers a full-moon circuit, a mountain-bike circuit and a walk in the Quebrada de la Peña.
What is El Hongo at Ischigualasto?
El Hongo, the Mushroom, is a wind-eroded column of pale sandstone with a broad cap on a narrow stem, standing on the valley floor at Ischigualasto, below the red cliffs of the Barrancas Coloradas. Wikipedia lists it among the park’s wind-cut formations, with the Submarine and the Sphinx.
What does the name Ischigualasto mean?
Sources differ. Wikipedia gives Ischigualasto as coming from the extinct Cacán language, meaning “place where the moon alights”; it also records a reading from the Diaguita meaning “dead land”, and a proposal of Huarpe roots.
Why is Ischigualasto a World Heritage Site?
UNESCO inscribed Ischigualasto and Talampaya National Park together in 2000 for their fossils. It describes the two parks as the only known area with a complete sequence of continental sediments, rich in fossil animals and plants, for the whole Triassic Period.