西貢區 Sai Kung District is the second largest district in Hong Kong in terms of area. It comprises the southern half of Sai Kung Peninsula in the New Territories plus a strip to the east of Kowloon. The administrative centre is Sai Kung Town but the district's population is concentrated in Tseung Kwan O New Town. The district has the second youngest residents.
Sai Kung District covers approximately 136 km² and as of 2006, it had a population of 406,442 in 2006, most of it in Tseung Kwan O.
In contrast to the densely populated areas of Hong Kong Island and Kowloon, Sai Kung District's heartland is a coastal area characterised by beautiful scenery, charming small villages and stunning seascapes. The area is known for its pristine beaches and quiet living. Inasmuch as it remains only partly urbanized, many people describe Sai Kung as the "last back garden" of Hong Kong.