By Emilia Wellesley · Published May 7, 2026 · Updated May 7, 2026
Standing on the Plateau: A Field Note Before the Survey
The Xieng Khouang plateau is a high country of red laterite and pine, a landscape that holds the late-afternoon light the way a fired clay tile holds heat — slowly, then all at once, in a low band that draws the carved sandstone jars out of the grass and gives every weathered rim its own narrow shadow. The Plain of Jars, in central-northern Laos, is not a single field but a constellation of more than a hundred sites scattered across hills, ridges, and ravines, and to walk the most-visited of them, the cluster known as Site 1 just outside Phonsavan, is to step into a place whose questions are older than any visitor’s vocabulary for them.
A local guide will point first to the marker stakes, the white concrete posts that delineate where unexploded ordnance has been cleared and where it has not, and then to the largest jar in the field, a tubular vessel about two and a half meters tall, with a single thick stone disc resting on its rim like a closed eye. The disc is the only one of its kind here. Most of the lids — if they were lids — are gone. The visitor’s first instinct is to ask what the jars were for, and the place’s first answer is to slow that question down. This guide traces what the plateau is now known to be, what the French archaeologist Madeleine Lucie Colani argued it was in the 1930s, what the Australian National University’s Plain of Jars Archaeological Project has added in the past decade, and where the work sits within the broader landscape of historical and archaeological mysteries.
What the Plain of Jars Is, Briefly
The Plain of Jars (Lao: Thong Hai Hin, “field of stone jars”) is a serial archaeological landscape of more than 2,100 carved megalithic stone jars distributed across over a hundred sites in the Xieng Khouang plateau of central-northern Laos. Radiocarbon and luminescence dating place its principal Iron Age use between roughly 500 BCE and 500 CE, with secondary mortuary activity continuing centuries later. UNESCO inscribed fifteen of the sites as a serial property in 2019, formally as the “Megalithic Jar Sites in Xiengkhuang — Plain of Jars” listing on the World Heritage List [4].
The Vessels Themselves
Each jar is a single piece of stone, mostly local sandstone with some limestone and granite, hollowed by hand and dressed on the outside, ranging between roughly one and three meters in height with rim diameters of about half a meter to a meter and a half. The largest jars weigh well over ten tonnes; some published estimates place a few above thirty. The most common form is a tapered cylinder, broader at the rim, narrowing slightly at the base, with no handles or footing. A handful carry decorative bands or shallow relief figures, but most are unadorned, their surfaces now patinated by lichen and the slow chemical work of laterite soil.
The Sites and the Province
The principal documented clusters lie within a roughly forty-kilometer radius of the provincial capital, Phonsavan. Site 1 (Ban Hai Hin), with about 316 jars set in five groups, is the largest and most accessible; Site 2 (Hai Hin Phu Salato) and Site 3 (Hai Hin Laat Khai) sit on forested hill spurs reached by paths through farmers’ fields. Outliers extend further afield, into Hua Phan and Luang Prabang provinces, and recent surveys by the Plain of Jars Archaeological Project have added more than twenty previously unrecorded sites to the inventory, deepening the impression of a regional culture rather than a single ceremonial center.
Madeleine Colani and the 1930s Expeditions
The first systematic archaeology of the plateau was conducted by Madeleine Colani (1866-1943), a French geologist-turned-prehistorian who arrived in colonial Indochina in 1898 and worked in the region for the rest of her life. She was, by 1929, mandated by the École française d’Extrême-Orient (EFEO) to coordinate prehistoric research in Laos, and in May 1931 she led the first formal archaeological mission to the Plain of Jars, summarised in the ANU School of Archaeology and Anthropology’s edition of Colani’s Megaliths of Upper Laos [1]. Over the next several seasons she and her team — including her sister Eléonore — surveyed and recorded twelve principal sites and produced a two-volume monograph, Mégalithes du Haut-Laos (Hua Pan, Tran Ninh), published by EFEO in 1935, which remains the indispensable point of departure for every subsequent study, including the new Australian-Lao fieldwork.
The Cave at Site 1
The most charged of Colani’s discoveries was the limestone cave that dominates the eastern end of Site 1. The cave’s mouth opens directly onto the largest concentration of jars in the field; inside, the rock has been worked, with two artificial holes pierced through the upper chamber that Colani interpreted as smoke vents. She excavated the floor and recovered burned human bone, ash, charcoal, glass and carnelian beads, fragments of pottery, and small bronze and iron objects. From this assemblage she developed a chambered-cremation hypothesis: the cave, in her reading, had functioned as a crematorium, and the great stone jars below it had served as containers for the ashes and grave goods of the cremated dead, a two-stage funerary architecture in which fire and stone divided the work of memorialization between them.
What She Got Right, and What She Could Not
Colani’s identification of the plateau as a regional Iron Age mortuary landscape — burials, cremations, secondary deposits, grave goods — has held up in every subsequent excavation. What she could not do, with the tools of 1935, was establish a secure absolute chronology, link the jar makers to a known cultural group, or test the cave-as-crematorium reading against a wider sample of sites. Her achievement was to walk the plateau with a notebook and a pickaxe and a precise eye, and to insist, against the colonial-romantic temptations of her own era, that the jars were not the leftovers of giants or the relics of legend but the work of a coherent human society whose practices could be reconstructed from the dirt.
The Vietnam War, the UXO Constraint, and the Decades of Silence
Between 1964 and 1973, the United States Air Force dropped more than two million tonnes of ordnance on Laos as part of the so-called Secret War, a covert campaign tied to the Vietnam War’s interdiction of the Ho Chi Minh Trail and the conflict between the Royal Lao government and the Pathet Lao. The Plain of Jars sat directly under this air war. Operation Barrel Roll and successor operations targeted the plateau as a strategic transit corridor, and the bombing was extraordinarily intense — by one widely cited reckoning, the equivalent of a planeload every eight minutes for nine years — with cluster munitions accounting for a large share of the total tonnage, as documented in the bombing-record compendium maintained by the Legacies of War project library [2].
The Cluster Bomb Legacy
Approximately one third of the anti-personnel cluster bomblets dropped on Laos failed to detonate, leaving the country, and Xieng Khouang province in particular, among the most heavily contaminated unexploded-ordnance landscapes in the world. For nearly thirty years after the war, archaeology on the plateau was effectively impossible. Many jars were damaged by direct hits or by clearance work, and entire sites lay inaccessible behind unmarked danger lines. The province’s farmers, working the same red laterite soil as in Colani’s day, lived inside the constraint that no archaeologist could ignore: every furrow, every house foundation, every excavation trench was preceded, if it could be preceded, by a clearance team.
The Clearance Teams Made the Work Possible
The resumption of systematic archaeology at the Plain of Jars rests on the patient and dangerous work of UXO Lao, the Mines Advisory Group (MAG), Norwegian People’s Aid, and the Lao National Regulatory Authority for UXO/Mine Action. These organizations established the cleared corridors and survey grids within which surveyors and excavators could place a transit, sink a test pit, or follow a magnetometer track. The recent Australian-Lao excavations have run inside that infrastructure of clearance from the first season, and any honest account of the modern archaeology has to begin by naming this debt. The plateau’s archaeological record, in a real sense, has been re-opened by mine-clearance technicians as much as by archaeologists.
The Plain of Jars Archaeological Project: O’Reilly, Shewan, and the New Generation
A renewed wave of fieldwork began in 2016, when the Plain of Jars Archaeological Project (PoJAP), an international Lao-Australian collaboration, opened a five-year excavation and survey programme co-directed by Dougald O’Reilly (Australian National University), Louise Shewan (University of Melbourne), and Thonglith Luangkhoth (Lao Department of Heritage). The project’s first major synthesis, “Excavating among the Megaliths: Recent Research at the ‘Plain of Jars’ Site 1 in Laos,” published in the Antiquity Project Gallery, appeared in 2019 [3] and remains the most detailed published account of modern excavation at the site.
What the Excavations Have Confirmed
The PoJAP excavations at Site 1 in 2016 and subsequent seasons confirmed and extended Colani’s basic mortuary reading. The team identified primary burials, secondary burials of disarticulated bone, and possible inhumation jars, accompanied by the same suite of grave goods Colani had recorded — glass and carnelian beads, iron implements, ceramic vessels, spindle whorls, bronze bells. Sandstone discs, limestone boulders, and quartz-veined blocks were used as grave markers around the jars themselves, suggesting a careful, formalized arrangement of burial space rather than a casual scatter.
What the Bioarchaeology Adds
The most consequential contribution of the new project is its bioarchaeology. Working with collaborators in physical anthropology, the PoJAP team has analyzed dental remains and isotopic signatures to begin asking who, in biological terms, the jar makers were — what they ate, where they grew up, how mobile they had been across their lifetimes. Subsequent radiocarbon, optically stimulated luminescence, and U/Pb zircon dating, published by Shewan, O’Reilly and colleagues in PLOS ONE in 2021, has clarified the chronology of jar emplacement and reuse, suggesting that some jars were placed in the landscape as early as the late second millennium BCE while burial activity around them continued into the second millennium CE — a usage history far longer than any single Iron Age culture.
Lia Genovese and the Wider Geographic Reach
In parallel with the PoJAP fieldwork, the SOAS-trained scholar Lia Genovese has spent two decades widening the geographic frame of the inquiry. Her 2015 doctoral dissertation, The Plain of Jars of North Laos — Beyond Madeleine Colani, and a 2020 article in the Journal of Lao Studies have catalogued previously unrecorded jar sites and traced typological links to megalithic mortuary traditions in highland Vietnam, Sabah in Malaysian Borneo, and Assam in northeastern India. The picture that emerges, taken together with PoJAP’s fieldwork, is of a Southeast Asian highland megalithic tradition wider, longer, and more interconnected than colonial-era scholarship was equipped to see.
Hypotheses, Mysteries, and the Disciplined Refusal to Resolve Them
It would be a relief, narratively, to say that the new excavations have settled the matter. They have not. They have refined Colani’s chambered-cremation reading without overturning it, and they have introduced a generation of new questions that the older method could not have asked.
Funerary, but Which Stage?
The strongest current consensus is that the jars served at one or more stages of a multi-stage funerary cycle. One possibility is Colani’s: the jars held cremated remains processed in nearby caves and sealed with stone disc lids. A second possibility, increasingly supported by the disarticulated-bone deposits PoJAP has recovered, is that the jars functioned as primary defleshing vessels, where bodies were left to skeletonize before the cleaned bones were buried separately around the jar. A third reading combines the two, with different jars and different sites serving different stages within an integrated regional practice. The evidence does not yet allow a single clean choice, and the disciplined position is to hold the readings open.
Who Carved Them, and Why Such Scale?
The makers remain anonymous. No surviving inscriptions, no contemporary texts, no clearly continuous local oral tradition reaches back to them. Recent detrital zircon analyses suggest the sandstone was quarried roughly eight kilometers from at least one major site, raising the same coordination-of-labor question that any megalithic site raises and the same patient answer: people moved very heavy stone for reasons that mattered to them. The jars are an argument that the highland Iron Age societies of mainland Southeast Asia commanded organizational capacity historians have only recently begun to credit.
Visiting the Plateau, Carefully
For the visitor — and the plateau is now open to visitors at Sites 1, 2, and 3, with marked walking paths and local interpretive signage — the visitor ethic begins with the marker stakes. White posts indicate cleared ground; red, uncleared. Walking off the marked paths is not a matter of curiosity, it is a matter of life. The local guides who run interpretive tours from Phonsavan are the first authority on what is safe to approach and what is not, and their narration weaves the archaeological record together with the war’s lived memory in a way no foreign monograph alone can deliver.
What to Watch For at Site 1
The capstoned jar, the limestone cave whose mouth opens onto the field, the bomb craters that punctuate the grass like negative monuments to a different era — these are the place’s primary documents. Read in their company, Colani’s 1935 monograph and the recent Antiquity paper become not academic objects but two further field notes in a record that visitors join when they walk the path. The plateau, in the sense the best travel writers have always meant the word, is the source. Everything else is annotation.
What the Place Asks of Us
The Plain of Jars sits at the intersection of an Iron Age mortuary tradition we are still reconstructing, a colonial archaeology that began the work in earnest, a war whose unexploded record is still in the soil, and a generation of Lao, Australian, and international scholars now reading the record together with the people who live on it. To name it a mystery is true and incomplete. The deeper claim is that the place keeps its questions on a long timescale, and that any honest writing about it has to keep its own answers proportionally patient. The jars will outlast the current literature, as they have outlasted every previous one. The work, for now, is to walk the field carefully, name the people who do the unglamorous parts, and credit the slow and ongoing repair of a landscape that almost vanished under the bombing.
Frequently Asked Questions
Where exactly is the Plain of Jars?
The Plain of Jars sits on the Xieng Khouang plateau in central-northern Laos, with the principal documented clusters within roughly forty kilometers of the provincial capital, Phonsavan. The largest single site, Site 1 (Ban Hai Hin), lies about ten kilometers southwest of the city. Outlying sites extend into Hua Phan and Luang Prabang provinces.
How old are the jars?
Combined radiocarbon, optically stimulated luminescence, and U/Pb zircon dating places the principal phase of jar use between roughly 500 BCE and 500 CE, the late prehistoric and early historic Iron Age of mainland Southeast Asia. Some jars may have been emplaced earlier and reused for secondary burial centuries later.
What were the jars used for?
The strongest current reading is funerary. Madeleine Colani in 1935 argued the jars held cremated remains processed in nearby caves; recent excavations by the Plain of Jars Archaeological Project have added evidence for primary and secondary burials around and possibly within the jars, suggesting a multi-stage mortuary practice rather than a single function.
Who was Madeleine Colani?
Madeleine Colani (1866-1943) was a French geologist and prehistorian who worked in colonial Indochina from 1898 and led the first systematic archaeological survey of the Plain of Jars between 1931 and 1933 under the auspices of the École française d’Extrême-Orient. Her two-volume Mégalithes du Haut-Laos (1935) remains the foundational study of the site.
Who is currently excavating the site?
Since 2016, the Plain of Jars Archaeological Project has been led by Dougald O’Reilly of the Australian National University and Louise Shewan of the University of Melbourne, working with Thonglith Luangkhoth of the Lao Department of Heritage and partner institutions including James Cook University and the University of Otago.
How many jars and how many sites are there?
More than 2,100 jars have been recorded across more than a hundred sites, with recent surveys by the Plain of Jars Archaeological Project adding more than twenty previously unrecorded sites to the inventory. The UNESCO World Heritage inscription covers fifteen of the principal sites.
Why is unexploded ordnance a constraint on archaeology here?
Between 1964 and 1973, the United States dropped more than two million tonnes of ordnance on Laos during the Vietnam War, with the Plain of Jars heavily targeted. About a third of the cluster bomblets failed to detonate. Mine-clearance organizations including UXO Lao, the Mines Advisory Group, and Norwegian People’s Aid have spent decades opening corridors that allow archaeology to resume.
When was the Plain of Jars made a UNESCO World Heritage Site?
The site, officially “Megalithic Jar Sites in Xiengkhuang — Plain of Jars,” was inscribed on the UNESCO World Heritage List in 2019 at the 43rd session of the World Heritage Committee. Fifteen of the principal jar sites are included in the serial property.
Are the jars connected to other megalithic traditions in Asia?
The scholar Lia Genovese has traced typological and ritual links between the Plain of Jars and megalithic mortuary traditions in highland Vietnam, Sabah in Malaysian Borneo, and Assam in northeastern India, suggesting a wider Southeast Asian highland phenomenon. The connections are stylistic and structural rather than evidence of direct contact.
Can visitors go to the site?
Yes. Sites 1, 2, and 3 are open to the public via marked walking paths cleared of unexploded ordnance, with local interpretive signage and guided tours run from Phonsavan. Visitors should follow the white-stake markers strictly; uncleared ground remains hazardous, and walking off the marked paths is not advised under any circumstances.
