Isabela's 1st congressional district is one of the six congressional districts of the Philippines in the province of Isabela. It has been represented in the House of Representatives since 1987. The district consists of the capital city of Ilagan and the northern municipalities of Cabagan, Delfin Albano, Divilacan, Maconacon, San Pablo, Santa Maria, Santo Tomas and Tumauini. It is currently represented in the 18th Congress by Antonio T. Albano of the National Unity Party (NUP).