China

"Mainland China" is a geopolitical term defined as the territory under direct administration of the Chinese Communist government of the People's Republic of China in the aftermath of the Chinese Civil War. The geopolitical sense of the term includes islands such as Hainan, Chongming, and Zhoushan, even though those islands are offshore of the Chinese mainland.[1] By convention, the territories that fall outside of the Mainland China include:

The term is widely used in all of the above territories as well as internationally, including by many Chinese diasporic communities.

 

Source: https://en.wikipedia.org/wiki/Mainland_China