The Ilocos Region (Ilocano: Rehion/Deppaar ti Ilocos; Pangasinan: Rehiyon na Ilocos; Tagalog: Rehiyon ng Ilocos), designated as Region I, is an administrative region of the Philippines. Located in the northwestern section of Luzon, it is bordered by the Cordillera Administrative Region to the east, the Cagayan Valley to the northeast and southeast, Central Luzon to the south, and the South China Sea to the west. The region comprises four provinces: Ilocos Norte, Ilocos Sur, La Union, and Pangasinan, along with one independent-component city, Dagupan City. The regional center is the city of San Fernando in La Union, which serves as the administrative hub of the region. The largest settlement in terms of population is San Carlos City in Pangasinan.
The 2020 Philippine Statistics Authority census reported that the ethnolinguistic group composition of the region is predominantly made up of Ilocanos (58.3%), followed by Pangasinans (29.7%), Tagalogs (4.1%), and various Cordilleran (Igorot) indigenous groups.
