The land that became Sai Kung District was ceded to British Hong Kong in 1898 under the Convention for the Extension of Hong Kong Territory, which added the New Territories to the existing colony. But settlement in the area predates the British presence by many centuries. Hakka fishing communities established coastal villages here from roughly the 14th century, building temples to Tin Hau and Hung Shing in sheltered anchorages. What makes Sai Kung historically distinctive, according to scholarly research, is that unlike many other New Territories areas, the villages here never coalesced into the powerful single-surname clans — the Dengs, Wens, and Liaos — that dominated politics elsewhere. The threat of pirates during the Qing dynasty kept communities diverse and defensive; mixed-surname villages bound by mutual protection rather than by lineage gave Sai Kung its particular social character, one that still marks the district today.

The phrase 'back garden of Hong Kong' is something of an understatement. Sai Kung District contains Sai Kung East Country Park and Sai Kung West Country Park, two of the largest protected areas in Hong Kong, together covering tens of thousands of hectares. The coastline alone — jagged, island-dotted, sheltered in some places and wild-surf-exposed in others — offers some of the finest hiking in South China. The 100-kilometre MacLehose Trail begins at Pak Tam Chung in Sai Kung, tracing a route from east to west across the hills. Tai Long Wan, accessible only on foot or by boat, is regularly cited as one of Hong Kong's most beautiful beach complexes, its four strands — Sai Wan, Ham Tin Wan, Tai Wan, and Tung Wan — separated by low headlands. The district also includes the Hong Kong UNESCO Global Geopark, a recognition of the extraordinary volcanic geology visible along the eastern coast.

There is an odd footnote in Sai Kung's identity: the Chinese characters for 'Sai Kung' — 西貢 — are also the Vietnamese Chữ Nôm characters for 'Saigon,' the former name of Ho Chi Minh City. This geographical coincidence occasionally causes confusion, especially since there is also a Saigon Street in Hong Kong, named after the Vietnamese city rather than the district. The two places share their written form entirely by accident, the result of different historical pathways through the same logographic system. Sai Kung's own name likely derives from its role as a local market — the Chinese characters can be parsed to mean something close to 'western tribute' or 'market port,' though the etymology is debated. Whatever its origins, the name has been in Western written records since at least the early 1900s.

The paradox of Sai Kung District is that its most populous place is a thoroughly modern new town. Tseung Kwan O, built on reclaimed land on the western edge of the district, has grown into a dense residential city of several hundred thousand people with its own MTR station, shopping malls, and schools. The district administrative office relocated there from the traditional centre at Sai Kung Town. Meanwhile, on the other side of the hills, Sai Kung Town itself remains relatively small — a seafood-famous, waterfront-facing community that feels, by Hong Kong standards, almost unhurried. The Hong Kong University of Science and Technology sits on the Clear Water Bay Peninsula within the district, one of the eight publicly-funded universities in Hong Kong and consistently ranked among the leading research universities in Asia. Science and tradition coexist within the same administrative boundary, a few mountain ridges apart.