Zambales's 1st congressional district is one of the two congressional districts of the Philippines in the province of Zambales. It has been represented in the House of Representatives since 1987. The district consists of the city of Olongapo and adjacent municipalities in the southernmost part of Zambales, namely Castillejos, San Marcelino and Subic. It is currently represented in the 20th Congress by Jefferson F. Khonghun of the Sulong Zambales Party (SZP) and LakasâÂÂCMD (Lakas).