Sulfur Hills of Pasil - Atlas Obscura

Sulfur Hills of Pasil

Pasil, Philippines

This steaming, yellow-tinged landscape is filled with sulfur-encrusted volcanic vents. 

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Within the mossy forests of Balatoc in the Kalinga province of the Philippines is an enthralling display of yellow soil and rocks known as the Sulfur Hills of Pasil. It serves as a testament to the existence of a once-majestic volcano and it continues to feature the beauty of what was left behind.

The Sulfur Hills are located at the lower slopes of Mount Binulunan (also known as Ambalatungan). The mountain is identified by the Philippine Institute of Volcanology and Seismology as an inactive volcano with possible. but unverified, eruptions in the 1950s and 1980s. This further explains the emergence of the Sulfur Hills, due to the mountain’s geothermal features stemming from its volcanic nature.

The hills have volcanic gases that seep out of the ground through fumarolic vents covered in sulfur. These vents also produce loud noises, accompanied by groundwater steam and the release of gases composed of hydrogen sulfide, carbon dioxide, and sulfur dioxide. The hills also have small and shallow caves in large yellow rock formations which makes it feel even more surreal. Stalactite-like deposits can also be found hanging from multiple rock walls.

Due to the dangerous composition of gases, the local government units implement strict safety measures for both community members and visitors. One of which is where infants, pregnant women, and anyone with heart or respiratory problems are not allowed anywhere near the steam.

The hills’ bright yellow formations hidden within lush pine tree forests, diverse waterfalls, and mountain boulders make the area a surreal paradise. There are also hot springs in the outer areas of the hills, at a distance that is safe enough for a relaxing soak. 

Excursions to the hills are grueling but visitors continue to arrive for another taste of adventure, to experience a different kind of utopia, and to satisfy their curiosity.

Know Before You Go

Be respectful of the community, their culture, and the environment when visiting the place. Balatoc, Pasil, is a 3-4 hour drive from Dagupan, Tabuk City, Kalinga, where a terminal for a jeepney going straight to Balatoc is located.


From Balatoc, another 3-4 hour hike is necessary to reach the Sulfur Hills. Visitors must not extend the duration of their stay to avoid prolonged exposure to the volcanic gases being released. Strictly follow the rules, instructions, and directions of guides.

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February 20, 2024

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