Yan Chau is part of the
Double Haven Special Area () that covers and was designated in 2011. The
special area includes the islets
Pak Ka Chau, Yan Chau (both within Double Haven) as well as the islet of
Ap Lo Chun and a part of
Ap Chau (both within
Crooked Harbour). The geology of the area is characterised by
sedimentary rocks of the
Jurassic and
Cretaceous periods. ==References==