Hong Kong Physical and human geographyadministrative region, China Chinese (Pinyin) Xianggang or (Wade-Giles) Hsiang-Kang

In sharp contrast to the low-lying areas of the Pearl River delta but conforming geologically and structurally to the great South China massif, a well-eroded upland region, Hong Kong has rugged relief and marked variations in topography. Structurally, the area is an anticline, running northeast-southwest, that was formed toward the latter part of the Jurassic Period (about 150 million years ago). Lava poured into this structure and formed volcanic rocks that were later intruded by an extensive granitic dome. The harbour of Hong Kong was formed by the drowning of the denuded centre of the dome. The surrounding hills on the mainland and on Hong Kong Island are partly capped by volcanic rocks, and steep, scarplike concave slopes lead to the inner harbour.

The area is a partially submerged, dissected upland terrain that rises abruptly to heights of more than 2,950 feet (900 metres); its backbone is made up of a series of ridges, running northeast to southwest, that tie in closely with the structural trend in South China. This trend is clearly observable from the alignment of Lantau Island and the Tolo Channel. From Mount Tai Mo—at 3,140 feet (957 metres) the highest peak in the territory—the series of ridges extends southwestward to Lantau Island, where the terrain rises to 3,064 feet on Lantau Peak and 2,851 feet on Sunset Peak. Extending southeastward from Mount Tai Mo, the Kowloon Peak attains an elevation of 1,975 feet, but there is an abrupt drop to about 650 feet at Devil’s Peak. Victoria (Hong Kong) Harbour is well protected by mountains on Hong Kong Island that include Victoria Peak in the west, which rises to 1,810 feet, and Mount Parker in the east, which reaches a height of about 1,742 feet.

Lowlands of the Hong Kong region, including floodplains, river valleys, and reclaimed land, occupy less than one-fifth of the land. Extensive lowland regions are found only north of Mount Tai Mo, in the Yuen Long and Sheung Shui plains. The urban area that spans the two sides of the harbour, with continued reclamation, takes up only about one-tenth of the level area.