Cambodia & Tourism: Stung Sen, the River That Carried Two Capitals

Between giant fruit bats, half-submerged water buffalo, and pre-Angkorian ruins swallowed by the forest, the Stung Sen River has watered the heart of Cambodia for over a thousand years — and quietly keeps sustaining one of the country's least-visited regions.

A fisherman heads upstream on the muddy waters of the Stung Sen at the end of the day, his motorized longtail boat gliding past the rooftops of Kampong Thom

As the sun sets over Kampong Thom, a low rumble rises from the tall trees surrounding the old colonial governor's residence. It builds by the minute, until hundreds of giant fruit bats suddenly break from the canopy and scatter over the brown waters of the Stung Sen in search of ripe fruit for the night. Below, on the riverbank, children are still playing in the current while water buffalo submerge themselves up to the neck to escape the heat of the day. This almost unchanging scene has repeated itself every evening for generations along the banks of a river that most visitors to Cambodia cross without even noticing — and yet one that gave rise to, then nurtured, two capitals thirteen centuries apart.

The Tonlé Sap's largest tributary

The Stung Sen (ស្ទឹងសែន) rises in the hills of Preah Vihear province in the north of the country, before winding more than 520 kilometers through Kampong Thom province to empty into the Tonlé Sap. Its watershed, covering 16,344 km², is the largest of the eleven major tributaries feeding the Great Lake — larger even than that of its neighbor, the Chinit River. Each year, the monsoon dumps around 1,500 millimeters of rain into the basin, swelling the river from a quiet trickle into a muddy torrent capable of submerging the surrounding banks and rice paddies for months at a time.

Isanapura, the forgotten capital of the Chenla kingdom

Long before Angkor existed, the region bordering the Stung Sen was the setting for another kind of grandeur. About thirty kilometers north of Kampong Thom, hidden beneath dense forest, the site of Sambor Prei Kuk — literally "the temple in the richness of the forest" — holds the remains of Isanapura, the capital of the pre-Angkorian Chenla kingdom, founded by King Isanavarman I in the early 7th century. More than a hundred brick temples still stand here, including ten octagonal towers unique of their kind in Southeast Asia, overrun by the roots of centuries-old kapok trees. The surviving sandstone lintels and pediments, carved with floral motifs and enigmatic scenes, are considered by archaeologists to be the founding models for the later Khmer art of the Angkorian period. Inscribed as a UNESCO World Heritage Site in 2017, Sambor Prei Kuk nonetheless remains one of the country's great archaeological sites least visited by tourists, far from the crowds drawn to its far more famous heir, Angkor Wat.

The town that took the river's name

Downstream, the river lent its name to the town that grew up on its banks: Kampong Thom, the provincial capital, is officially named Stung Sen — a name most Cambodians actually use more readily than "Kampong Thom," the one better known to travelers.

In the town center, a metal sculpture shaped like fish, guarded by two stone lions, is a reminder that Kampong Thom owes its very existence to the river that feeds it

The town itself is nothing spectacular: a few dusty streets, a market, an old governor's residence in crumbling colonial style. It's precisely in the overgrown garden of that residence that the colony of giant fruit bats roosts, drawing the handful of visitors who pass through each evening — a cluster of enormous trees whose canopies are said by locals to shelter several hundred individuals.

Beneath a century-old tree, a statue pays tribute to Khmer peasants of old, carrying water and harvests through the seasons, in front of a traditional house freshly painted red.

A wooden shed overrun with vines, just steps from the river, reflects the weathered, slightly neglected charm still found at the heart of Kampong Thom

Everyday life along the water

Perhaps it's this absence of any single grand monument that makes the Stung Sen so endearing: above all, it remains a river of work and daily life. On the riverbank, right by the market, motorbikes pull up in front of makeshift stalls selling shrimp and shellfish, laid out directly on the ground among woven baskets.

A mother and her son stop on their motorbike in front of makeshift stalls selling shrimp and shellfish, set up right on the ground of the riverbank

A little further along, under colorful umbrellas, vendors scale and cut up the day's fresh catch, pulled from the nearby current just hours earlier.

The fish market stretches all along the riverbank, mats piled high with carp and catfish freshly pulled from the river

Two young girls take a moment to relax between stalls, while a little further upstream, a houseboat with a rusted tin roof is a reminder that some families still live on the water year-round.

Moored close to the bank, a houseboat with a rusted tin roof illustrates the river-based way of life still practiced by some fishing families on the Stung Sen

Along the shore, traditional Khmer stilt houses with brightly painted staircases stand next to basket-weaving stalls piled high with large rattan baskets used to carry rice and harvests.

A traditional Khmer stilt house, its staircase painted in bright colors, stands at the water's edge, shaded by two coconut palms

Rows of woven rattan baskets, used for carrying rice and harvests, lined up in front of a stall at the Kampong Thom market

Upstream and downstream of the town alike, whole families live by the rhythm of the river all the way to its mouth on the Tonlé Sap, where the floating village of Phat Sanday gathers fishing communities whose houses, mounted on rafts or floating barrels, rise and fall with the water level through the seasons.

A river under watch

This abundance isn't guaranteed forever. Part of the lower course of the Stung Sen, near its mouth on the Tonlé Sap, has been protected since 2001 as a wildlife sanctuary, recognized as a wetland of international importance under the Ramsar Convention in 2018 — a designation that underscores the crucial role these seasonally flooded zones play in the reproduction of the Great Lake's fish stocks. Further upstream, in Preah Vihear province, a hydropower dam project on the Stung Sen has been under study for several years. If built, the dam would flood part of the river's upper course and could, according to environmental groups, affect the flood cycles that the entire Tonlé Sap fishery depends on — a reminder that even Cambodia's most unassuming rivers are never entirely shielded from large-scale development projects.

How to explore the Stung Sen

Kampong Thom sits roughly halfway between Phnom Penh and Siem Reap on National Road 6, making it a natural stopover for travelers moving between the two cities. A late-afternoon walk along the riverbanks to the old governor's residence and its bat colony remains one of the simplest ways to take the town's pulse. For visitors with more time, a boat trip from the central market down to the floating village of Phat Sanday covers the full downstream stretch of the river, while Sambor Prei Kuk, a short hour's drive from town, offers a rare immersion into the origins of Khmer civilization, far from the crowds of Angkor.