Zambales's at-large congressional district refers to the lone congressional district of the Philippines in the province of Zambales for various national legislatures before 1987.[1] The province elected its representatives province-wide at-large from its reorganization under Article 6 of the Decreto de 18 junio de 1898 y las instrucciones sobre el régimen de las provincias y pueblos for the Malolos Congress in 1898 until the reapportionment in 1987 under Section 1 of the ordinance annex of the 1987 Constitution of the Philippines which created its first and second districts.[2][3] It was a single-member district throughout the ten legislatures of the Insular Government of the Philippine Islands from 1907 to 1935, the three legislatures of the Philippine Commonwealth from 1935 to 1946, the seven congresses of the Third Philippine Republic from 1946 to 1972, and the national parliament of the Fourth Philippine Republic from 1984 to 1986.[1]
On two occasions in its history, Zambales sent more than one member to the national legislatures who were also elected or appointed at-large. Three representatives were sent to the National Assembly (Malolos Congress) of the First Philippine Republic from 1898 to 1901 and two representatives to the National Assembly of the Second Philippine Republic from 1943 to 1944.
After 1986, all representatives were elected from its two congressional districts.[1]