Hefei (həˈfeɪ; ) is the capital and largest city of Anhui Province, People's Republic of China. A prefecture-level city, it is the political, economic, and cultural center of Anhui. Its population was 9,369,881 as of the 2020 census and its built-up (or metro) area made up of four urban districts plus Feidong, Feixi and Changfeng counties being urbanized, was home to 7,754,481 inhabitants. Located in the central portion of the province, it borders Huainan to the north, Chuzhou to the northeast, Wuhu to the southeast, Tongling to the south, Anqing to the southwest and Lu'an to the west. A natural hub of communications, Hefei is situated to the north of Chao Lake and stands on a low saddle crossing the northeastern extension of the Dabie Mountains, which forms the divide between the Huai and Yangtze rivers.
The present-day city dates from the Song dynasty. Before World War II, Hefei remained essentially an administrative centre and the regional market for the fertile plain to the south. It has gone through a growth in infrastructure in recent years. Hefei is the location of Experimental Advanced Superconducting Tokamak, an experimental superconducting tokamak magnetic fusion energy reactor.
Hefei is a world leading city for scientific research, with its ranking placed at 16th globally, 8th in the Asia-Pacific and 6th in China (behind Beijing, Shanghai, Nanjing, Guangzhou and Wuhan), as tracked by the Nature Index in 2022. The city is represented by several major universities, including the University of Science and Technology of China, Hefei University of Technology, Anhui University, Anhui Agricultural University and Anhui Medical University. Notably, the University of Science and Technology of China is one of the top 100th comprehensive public research universities in the world.
From the 8th to the 6th centuries BC, Hefei was the site of many small states, later a part of the Chu kingdom. Many archaeological finds dating from this period have been made. The name 'Hefei' was first given to the county set up in the area under the Han dynasty in the 2nd century BC.