East Dam of High Island Reservoir

Rock-column Palace (Half-day course)

The High Island Geo Trail at the East Dam of the High Island Reservoir is an appealing route, offering beautiful vistas of the reservoir and the surrounding verdant hills, as well as magnificent hexagonal volcanic rock columns. This easily accessible scenic spot is among Sai Kung’s most popular natural attractions. It is also an ideal location for observing the world-class hexagonal rock columns at close range.

Visitors will find interpretation plates and picnic facilities along the High Island Geo Trail, which is a generally level and easy trail, suitable for all hikers. This idyllic country course winds along sheer rock cliffs, with giant columns plummeting up to a hundred feet to the ground. The visitor’s gaze takes in the beautiful coastline, which stretches for miles, and endless clusters of tall rock columns, revealing the genius and grandeur of nature. The newly opened Biu Tsim Kok extension of the geo trail offers a panoramic vista across the ancient High Island caldera, the delightful Long Ke Wan, and the idyllic High Island Reservoir.

The hexagonal columnar rock formations in Hong Kong are products of devastating volcanic eruptions about 140 million years ago. They were formed in specific conditions when masses of scorching molten volcanic materials underwent condensational contraction. They are different from hexagonal rock columns found elsewhere in both rock texture and chemical composition, making them globally important geo-wonders. They are also vastly distributed and occur in large diameter.

Looking toward the sea from East Dam, Fa Shan is cut into two parts; the one being separated is Po Pin Chau, which is a type of the sea abrasion landscapes - sea stack. Po Pin Chau was once part of Fa Shan, but years of wave impact and erosion separated it. The rock stacks on the shore of Po Pin Chau tower almost vertically over the sea. The rock face looks just like a giant pipe organ.

About 140 million years ago, when the columns were still in a semi-plastic state, they were distorted into an S-shape under the influence of earthquakes and regional subsidence. The distorted area of the rock columns is the most vulnerable. During geological processes, magma intruded along the weak line of the columns and cooled to form an intrusive dyke, which is about 40 million years younger than the surrounding rocks.

Rock columns elsewhere are usually made of dark grey basalt with low silica content. By contrast, the rock columns in Hong Kong are light-coloured, silica-rich, rhyolitic volcanic rock. The columnar joints are mainly pentagonal or hexagonal. It is estimated that the columns cover an area of over 100 km2 (including submerged areas), with an exposed height up to 100m, a total thickness of 400m and an average diameter of 1.2m. The rock columns have features of both tuff and lava, but there is still no consensus among geologists on the material that formed them.

East Dam of High Island Reservoir

Rock-column Palace (Half-day course)

Half-day Trip to High Island Reservoir

How to Explore East Dam of High Island Reservoir

Video of High Island

Key of Attraction

Reservoir Monument

History of Reservoir

Geopark Monument

Hexagonal Rock Columns

Po Pin Chau (sea stack)

Cofferdam

S-shaped Hexagonal Columns

Sea Cave

Waymark

Long Ke Wan

Viewing Point

Volcanic Rock Wall

Location Map of High Island

Enjoy Your Geopark Journey.