Bulacan's 1st congressional district is one of the seven congressional districts of the Philippines in the province of Bulacan. It has been represented in the House of Representatives of the Philippines since 1916 and earlier in the Philippine Assembly from 1907 to 1916. The district consists of the provincial capital city of Malolos and adjacent municipalities of Bulakan (Bulacan), Calumpit, Hagonoy, Paombong and Pulilan. Until its second dissolution in 1972, it also consisted of Balagtas (formerly Bigaa), Bocaue, Bustos, Guiguinto , and Plaridel (formerly Quingua). It is currently represented in the 20th Congress by Danilo A. Domingo of the National Unity Party (NUP).
In 2010, due to the Supreme Court ruling the creation of the congressional district of Malolos as unconstitutional, the election at Bulacan's 1st congressional district originally scheduled for May 2010 was delayed. The ballots were originally printed with Malolos having a different set of candidates from the rest of the 1st district. In the May 2010 general election, balloting for the 1st district was still done, showing incumbent Ma. Victoria Sy-Alvarado with an overwhelming lead over Governor Roberto Pagdanganan in the 1st district, and Danny Domingo also having a majority of the vote in Malolos.
The COMELEC later on ruled that the candidates that were listed in Malolos and the rest of the 1st district shall contest the election. Domingo and Aniag withdrew, Cruz and Valencia did not campaign, while only Sy-Alvarado and Pagdanganan campaigned. Sy-Alvarado won in November 2010.