Hong is the pinyin romanization of the Chinese surname 洪 (Hóng). It was listed 184th among the Song-era Hundred Family Surnames. Today it is not among the 100 most common surnames in mainland China but it was the 15th-most-common surname in Taiwan in 2005. As counted by a Chinese census, Taiwan is the area with the largest number of people with the name. It is also the pinyin romanization of a number of less-common names including Hóng (弘), Hóng (t 閎, s 闳), and Hóng (宏). All of those names are romanized as Hung in Wade-Giles.
"Hong" is also one spelling employed for the Cantonese pronunciation of the surname Xiong (熊).
The Hokkien and Teochew romanization of Hong (that uses the character 洪) is Ang, which is also used for Wang (汪, Wāng).
It is also the romanization used for the Korean surname Hong, which uses the character 洪 in hanja, the Khmer surname ហុង (Hong), as well as the surname Hồng in Vietnam, from the Sino-Vietnamese reading of Chinese character 洪.