The Convoluted History of the Fourth Largest Island of Hong Kong

Besides Kowloon and the New Territories mainland, which are attached to the Chinese mainland, Hong Kong is made up of 263 islands. Of these, Lantau Island (the largest), Hong Kong Island (the second-largest yet most populated), and Lamma Island (the third-largest) are the most well-known.

The fourth-largest island in the territory, on the other hand, has an interesting story. Since the mid-1990s, Chek Lap Kok, covering 12.7 square kilometres (4.9 square miles), has held this title. However, prior to the massive land reclamation required to build the new Hong Kong International Airport, Chek Lap Kok was a small, 3.02-square-kilometre (1.17 sq mi) island, while Lam Chau—the other island swallowed up to form present-day Chek Lap Kok—measured a mere 0.08 square kilometres (0.031 sq mi).

In fact, the fourth-largest island of Hong Kong was historically High Island, or Leung Shuen Wan. Situated on the southeastern edge of Sai Kung, it originally measured 8.5 square kilometres (3.28 square miles). Yet, it didn’t lose its title to Chek Lap Kok's expansion. Instead, it ceased to be an island altogether after being connected to the mainland via dams between 1971 and 1978 to create the High Island Reservoir.

Still, one might wonder why the larger Tsing Yi Island, measuring 10.69 square kilometres (4.13 square miles), wasn’t historically the fourth-largest island. The answer lies in the fact that, prior to successive land reclamations from the mid-1970s to the late 1980s, Tsing Yi Island only measured 6.2 square kilometres (2.4 square miles).