Longshan Social Democratic Party

The Longshan Social Democratic Party (Chinese: 龙山社会民主党, Pinyin: Lóngshān Shèhuì Mínzhǔdǎng, POJ: Liông-san Siā-hōe Bîn-tsú-tóng) is the branch of the Social Democratic Party of Enderron operating in Longshan Prefecture. The party is the one of the two major political parties in Longshan politics, the other being the Liberal Party of Longshan. The current party leader is Premier Miles Liu, since 2013. It has been the governing party of Longshan since 2006.

The Longshan SDP is the strongest Social Democratic branch in northern Enderron, with Longshan being the party's only stronghold in an otherwise generally conservative region. The party has formed the government of Longshan over five periods: 1946 to 1952, 1969 to 1974, 1978 to 1982, 1990 to 2002, and 2006 to the present.

Historically weaker than the United Party, the Social Democrats have come to dominate Longshan politics since the 1970s, and especially since the 1990s. The party has held a majority of Longshan's seats in the Enderronian Parliament continuously since the 1970 federal election.