"Mainland China" is a geopolitical term defined as the territory under direct administration of the People's Republic of China (PRC) in the aftermath of the Chinese Civil War. In addition to the geographical mainland, the geopolitical sense of the term includes islands such as Hainan, Chongming, and Zhoushan.
By convention, the following territories are excluded from the term:
Special administrative regions of China, which are regarded as subdivisions of the country, but retain distinct administrative, judicial and economic systems from those on the mainland:
Hong Kong, formerly a British colony
Macau, formerly a Portuguese colony
Taiwan, along with Penghu, Kinmen, Matsu and other minor islands, are collectively known as the Taiwan Area, where has been the major territorial base of the government of Taiwan (ROC) since 1950. The ROC still claims the "Mainland Area" as its constitutionally defined territory.
In Taiwan, the term is often used to refer to all territories administered by the PRC. The term is widely used in Hong Kong, Macau, and Taiwan as well as internationally, including by many Overseas Chinese communities and diasporas.
In 1949, the Chinese Communist Party (CCP) and the People's Liberation Army had largely defeated the Kuomintang (KMT)'s National Revolutionary Army in the Chinese Civil War. This forced the Kuomintang to relocate the government and institution of the Republic of China to the relative safety of Taiwan, an island which was placed under its control after the surrender of Japan at the end of World War II in 1945. With the establishment of the People's Republic of China on 1 October 1949, the CCP-controlled government saw itself as the sole legitimate government of China, competing with the claims of the Republic of China, whose authority is now limited to Taiwan and other islands. This resulted in a situation in which two co-existing governments competed for international legitimacy and recognition as the "government of China". With the democratisation of Taiwan in the 1990s and the rise of the Taiwanese independence movement, some people began simply using the term "China" instead.
Due to their status as colonies of foreign states during the establishment of the People's Republic of China in 1949, the phrase "mainland China" excludes Hong Kong and Macau. Since the return of Hong Kong and Macau to Chinese sovereignty in 1997 and 1999, respectively, the two territories have retained their legal, political, and economic systems. The territories also have their distinct identities. Therefore, "mainland China" generally continues to exclude these territories, because of the "one country, two systems" policy adopted by the Chinese government towards the regions. The term is also used in economic indicators, such as the IMD Competitiveness Report. International news media often use "China" to refer only to the mainland of the People's Republic of China.
The Exit and Entry Administration Law of the People's Republic of China (Chinese: 中华人民共和国出境入境管理法) defines two terms in Chinese that are translated to "mainland":
Dàlù (大陆; 大陸), which means 'the continent'.
Nèidì (内地; 內地), literally 'inland' or 'inner land'. It excludes Hong Kong and Macau.
In the PRC, usage of the two terms is not strictly interchangeable. To emphasise the One-China policy and not give the ROC "equal footing" in cross-strait relations, the term must be used in PRC's official contexts with reference to Taiwan (with the PRC referring to itself as the "mainland side" dealing with the "Taiwan side"). In fact, the PRC government mandates that journalists use "Taiwan" and "the Mainland" (Dàlù) as corresponding concepts.
But in terms of Hong Kong and Macau, the PRC government refers to itself as "the Central People's Government". In the People's Republic of China, the term 内地 (Nèidì, 'inland') is often contrasted with the term 境外 ('outside the border') for things outside the mainland region. Examples include "Administration of Foreign-funded Banks" (中华人民共和国外资银行管理条例; 中華人民共和國外資銀行管理條例) or the "Measures on Administration of Representative Offices of Foreign Insurance Institutions" (外国保险机构驻华代表机构管理办法; 外國保險機構駐華代表機構管理辦法).
Hainan is an island, but is nevertheless commonly considered to be part of the "mainland" politically, because its government, legal and political systems do not differ from the rest of the PRC. Nonetheless, Hainanese people still refer to the geographic mainland as "the mainland" and call its residents "mainlanders".
Before 1949, the Kinmen and Matsu islands, were jointly governed with the rest of Fujian Province under successive Chinese governments. The two territories are generally considered to belong to the same historical region, Fujian Province, which has been divided since 1949 as a result of the civil war. However, because they are not controlled by the PRC, they are not included as part of "mainland China".
Some Internet platforms like Bilibili bans the term "mainland China" on their website and considered its use promoting separatism and undermining the integrity of national sovereignty. They require that the term should be replaced as "Chinese mainland", "China's mainland" and "the mainland of China". According to the Foreign Ministry of the People's Republic of China, "Chinese mainland" is the correct term because "mainland China" supposedly implies that there are other Chinas.
Hong Kong and Macau have been territories of the PRC since 1997 and 1999 respectively. However, due to the One Country, Two Systems policy, the two regions maintain a degree of autonomy, hence they are not governed as part of mainland China.