Ilocos region or Region I (Ilokano: Rehion ti Ilocos, or Deppaar ti Ilocos; Pangasinan: Rihiyon na Sagor na Baybay na Luzon) of the Philippines is located in the northwestern region portion of Luzon. It is bounded by the Cordillera Administrative Region and Cagayan Valley to the east, Central Luzon to the south and by the South China Sea to the west.
Region I occupies the narrow plain between the Cordillera Central mountain range and the South China Sea. It also occupies the northern portion of the Central Luzon plain, to the north-east of the Zambales Mountains.
Lingayen Gulf is the most notable body of water in the region and it contains a number of islands, including the Hundred Islands National Park. To the north of the region is Luzon Strait.
The Agno river runs through Pangasinan and empties into the Lingayen Gulf. The river flow into a broad delta in the vicinity of Lingayen and Dagupan City.
It has a total land area of 12, 840.19 sq. km. the Province of Pangasinan covers the largest with about 41.8% while La Union is the smallest with only 11.6%. The region land area comprises about 4.28% of the total land area of the Philippines.
Region I more popularly known as the LuPangIlocos Region comprising of four (4) provinces: Pangasinan, La Union, Ilocos Sur, and Ilocos Norte and nine (9) cities namely: Dagupan City (Highly Urbanized), San Carlos City, Alaminos City and Urdaneta City in Pangasinan; Candon City and Vigan City in Ilocos Sur; Batac City and Laoag City in Ilocos Norte; and the regional capital is the City of San Fernando, La Union. There are 116 municipalities and 3, 265 barangays.