A Chau (Chinese: 鴉洲) is a small uninhabited island in the inner most of Starling Inlet (Sha Tau Kok Hoi), off Nam Chung,[1] in the north-eastern New Territories of Hong Kong.

It is under the administration of North District, and falls within the Closed Area.

A Chau has been designated as a Site of Special Scientific Interest since 1985.

[2] The fauna of the island includes night heron, little egret, great egret, black-headed gull and herring gull.

[1] It was reported in 2007 that A Chau was the largest egretry in Hong Kong and may also have been one of the most important night roosting sites for the ardeids in winter.