The Ancient Potholes (150 Million Years Old) in Lahan Sai District, Buriram Province, represent one of Thailand’s rare and scientifically significant geological phenomena. Their origin dates back to approximately 150 million years ago during the Mesozoic Era, when this region was once part of an ancient river system or a broad floodplain with continuously flowing water.

At that time, large amounts of sand, gravel, and sediment were transported and deposited within unconsolidated sandstone layers. Over millions of years, these sediments gradually lithified into solid sandstone, though still vulnerable to erosion by natural forces.

As ancient water currents flowed across the area, vortex motion combined with trapped gravel and sand began to erode the rock surface. This process, known as swirl erosion, acted like a natural drilling system, slowly grinding and carving the sandstone over millions of years. This continuous erosion formed deep cylindrical or inverted cone-shaped holes known as “potholes” or “kumphalak.”

Because the intensity of water flow and sediment load varied over time, each pothole developed differently in size and depth. Some are as small as 40 centimeters, while others reach up to 3 meters in diameter, with depths extending as far as 40 meters. These variations clearly reflect the powerful hydrodynamic forces of ancient river systems and indicate a much wetter prehistoric environment compared to today.

The site sits on a vast sandstone plateau of approximately 17 rai, containing more than 16 well-preserved potholes, making it one of the most complete pothole fields in Thailand.

Historically, the site was first discovered by local villagers around 1959, and later between 1975–1982, it was reportedly used as a temporary shelter by members of the Thai Communist insurgent movement (CPN/CT) due to its natural rock formations and protective landscape features.

In addition, local beliefs once regarded these potholes as sacred natural formations, where collected rainwater was sometimes used in rituals or traditional healing practices. Although such beliefs have declined today, they remain part of the region’s cultural heritage.

From a scientific perspective, this site is highly valuable for studying fluvial erosion processes and paleogeography. It helps geologists reconstruct ancient river dynamics and understand environmental conditions in Southeast Asia millions of years ago.

Furthermore, the site provides important evidence of long-term crustal evolution and sedimentary processes, illustrating how the northeastern region of Thailand transitioned from a water-rich ancient landscape into the relatively dry plateau seen today.

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How to Get There

• By car: From Buriram city, take Highway 218 toward Nang Rong District, then continue onto Highway 348 toward Lahan Sai District. Enter Samrong Mai Subdistrict and Ban Santi Suk village, then travel approximately 1.5 km to the site.

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Travel Tips

• Bring drinking water and sun protection as the area is open and hot

• Early morning or late afternoon is best for photography

• Be careful when walking near deep potholes and rocky surfaces

• Do not litter and help preserve the natural environment

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Admission Fee:

• Free of charge

Opening Hours:

• Open daily from 8:00 AM – 5:00 PM (may vary depending on local conditions)