Territorial changes of the People's Republic of China

• 1 October 1949. The establishment of the People's Republic of China was officially announced by Mao Zedong (ruled from 1949 until 1976) on the Tiananmen in Beijing. On 13 October 1949 annexation of Xinjiang into the People's Republic of China.
• 1 May 1950, the Island of Hainan was fully under control of the PLA.[1]
• 19 May 1950, the largest archipelago of China - Zhoushan, was fully under control of PLA.[2]
• 23 May 1951, area of Tibet Autonomous Region was claimed as an annex to the People's Republic of China.
• 3 September 1954, The People's Republic of China annexed the Yijiangshan Islands and Dachen Islands from the Republic of China during the First Taiwan Strait Crisis (Battle of Yijiangshan) even as the U.S. Seventh Fleet was patrolling nearby.[3]

• 21 November 1962, China won the military victory of Sino-Indian War but withdrew to the pre-war boundaries. Since then, India maintains control of North-East Frontier Agency area ie Arunachal Pradesh; China controls areas of Aksai Chin (~30,000 /33,444/37,555 km²)[4] and Trans-Karakoram Tract (5,181/5,180 km²). See article: Sino-Indian War.
• 1969, after Sino-Soviet border conflict, Soviet Union controlled Zhenbao Island (see article: Sino-Soviet border conflict). (Extra mark: Control of Zhenbao Island later was granted to China in the 2000s, see article: 1991 Sino-Russian border agreement).

• 25 October 1971, The People's Republic of China replaced the Republic of China (in Taiwan) in the UN seat representing China. The PRC claims Taiwan as its own province, despite never having gained control over it. See articles: China and the United Nations, Political status of Taiwan.
• 19 January 1974, after the Battle of the Paracel Islands, China controls over the Paracel Islands and surrounding waters. See article: Battle of the Paracel Islands.

• 14 March 1988, after the Johnson South Reef Skirmish, China controls (at least) 6 reefs in the South China Sea: Fiery Cross Reef, Cuarteron Reef, Hugh Reef/Hughes Reef, Nanxun Jiao/Nanxun Reef, Subi Reef, Chigua Jiao/Chigua Reef, and surrounding waters. See article Johnson South Reef Skirmish.

• 1991, after the 1991 Sino-Russian Border Agreement, many segments of territories and islands along the border between China and Russia were transferred to China. See article: 1991 Sino-Russian Border Agreement.
• 1 July 1997, Hong Kong, leased to the British for 99 years, (1,104 km²) returned to Chinese control. See article Transfer of sovereignty of Hong Kong.
• 1998-1999, the Sino-Russian-North Korean border was fixed.
• 20 December 1999, Macau (29.2 km²) was handed to China. See article: Transfer of sovereignty of Macau.

• 14 October 2004 – 2 June 2005, a treaty establishing the eastern border between P.R.China and Russia was signed by P.R.China and Russia. It's said China "regained 337 km²" territory. See Russian article: Демаркация российско-китайской границы (2005); Chinese article: 中华人民共和国和俄罗斯联邦关于中俄国界东段的补充协定.
• September 2008 – 2009, the border between China and Tajikistan was surveyed. It's said that China "regained more than 1,000 km²".[5]
• 31 December 2008, the borderline between P.R.China and Vietnam was determined, but detailed information hasn't yet been published.[6]
• 2009, the artificial land (mainland China only) built by the nation would be 150 km².[7]

• 12 January 2011: The Tajikistan parliament ratifies a deal ceding approximately 1000 square kilometres to China.[8][9]

• 2012, after Scarborough Shoal standoff, P.R.China gains control over some parts of Scarborough Shoal in the South China Sea but the claims are still going on.[10]

^ a:  "... 1045万平方公里，其中陆地940万平方公里，岛屿75400平方公里，滩涂12700平方公里，内海693000平方公里，领海22万平方公里" -- 《中国领土面积》(The territory of China); 1986年4月20日《信息日报》 (20 December 1986; Daily Information)

Daily Information is a Chinese newspaper founded on 1 October 1984, reporting economic and communications news. See the introduction to the newspaper (in Chinese): 《信息日报》