[1][2] Originally, Hapjeong-dong was a part of Yeonhui-bang, a division of Seoul that encompassed approximately Seodaemun District and the western part of Mapo District.

The meaning of Hapjeong-dong, written in Hanja as 蛤井洞, was "clam well".

Later the Hanja transcription of Hapjeong was changed to 合井.

After the Japan–Korea Annexation Treaty of 1910, Hapjeong-dong was known as Hapjeon-ri in 1913 and Hapjeong-jeong in 1936; it was a part of Yeonhui-myeon, which extended from Seodaemun District to Yeouido.

[3] Hapjeong-dong contains the following main streets, which also give their name to surrounding, smaller streets according to the new address system in South Korea: A few historical landmarks may be found in Hapjeong-dong: Other notable sites in Hapjeong-dong include: A number of companies specialized in music or media are located in Hapjeong-dong, included YG Entertainment.