Mapo A (Korean: 마포구 갑) is a constituency of the National Assembly of South Korea. The constituency consists of portions of Mapo District, Seoul. As of 2020, 157,500 eligible voters were registered in the constituency. The constituency was created in 1988 from the Mapo–Yongsan constituency.

Throughout its history, Mapo A has voted for members of both conservative and liberal parties to represent the constituency. The liberal Peace Democratic Party's Roh Seung-hwan was the first to represent Mapo A in the National Assembly from May 30, 1988, to May 29, 1992. Roh left the Democratic Party^{[lower-alpha 1]} on February 9, 1992, due to the party not nominating him as its candidate for the constituency and refused to stand for election in the 1992 legislative election.^[1] He was succeeded by Park Myung-hwan of the conservative Democratic Liberal Party (later known as the New Korea Party) who represented the constituency from May 30, 1992, to May 29, 2004. Noh Woong-rae, the son of Roh Seung-hwan, won the constituency in the 2004 legislative election as a member of the liberal Uri Party. However, he lost the seat in the following election to Kang Seung-kyu of the conservative Grand National Party by a difference of 1,680 votes.^[2] Noh won back the seat in the 2012 legislative election and has served as Mapo A's member of the National Assembly since then, until 2024.^[3]

In the course of the 2024 South Korean legislative election, the Democratic Party, which Noh is a member of, labelled Mapo A as a "strategic constituency" and nominated former police officer Lee Ji-eun as the party's candidate for the constituency.^[4] Noh had previously been investigated and indicted by the Seoul Central District Prosecutor's Office on charges of bribery and violating South Korea's Political Funds Act.^[5] Noh strongly opposed the party's decision to not nominate him and began a hunger strike on February 22, 2024.^[6] He ended his hunger strike on March 9, 2024, citing that the party leadership had refused to reconsider their decision.^[7]

Cho Jung-hun of the People Power Party is the current MP for this constituency, having won a tight fight in the 2024 elections against aforementioned candidate Lee Ji-eun from the Democratic Party.

The constituency encompasses the neighborhoods of Ahyeon-dong, Gongdeok-dong, Dohwa-dong, Yonggang-dong, Daeheung-dong, Yeomni-dong, and Sinsu-dong.

• List of constituencies of the National Assembly of South Korea