Abra (province) in the context of Bangued, Abra

Ilocos Norte (English: Northern Ilocos/North of Ilocoscode: eng promoted to code: en ), officially the Province of Ilocos Norte (Ilocano: Probinsia ti Ilocos Norte; Tagalog: Lalawigan ng Ilocos Norte), is a province of the Philippines located in the Ilocos Region. It is located in the northwest corner of Luzon island, bordering Cagayan and Apayao to the east, and Abra to the southeast, and Ilocos Sur to the southwest. Ilocos Norte faces the South China Sea to the west and the Luzon Strait to the north. Its capital is Laoag, which is the most populous settlement in the province.

Ilocos Norte is noted for its distinctive geography and culture. This includes numerous examples of well-preserved Spanish colonial era architecture, particularly Saint William's Cathedral in Laoag with its sinking bell tower constructed in the Earthquake Baroque style, the St. Augustine Church in Paoay which is one of UNESCO's World Heritage Sites in the Philippines, and the Cape Bojeador Lighthouse. Famous geographical features include the La Paz Sand Dunes, the beaches of Pagudpud, and the eroded calcarenite Kapurpurawan rock formation in Burgos.

Ilocos Sur (lit. 'South Ilocos'), officially the Province of Ilocos Sur (Ilocano: Probinsia ti Ilocos Sur; Tagalog: Lalawigan ng Ilocos Sur), is a province in the Philippines located in the Ilocos Region in Luzon. Located on the mouth of the Mestizo River is the capital of Vigan, while Candon is the most-populous city. Ilocos Sur is bordered by Ilocos Norte and Abra to the north, Mountain Province to the east, La Union and Benguet to the south and the South China Sea to the west.

Ilocos Sur was established in 1818 when the province of Ilocos was split into two: the north (now Ilocos Norte) and the south (Ilocos Sur). At that time, it included parts of Abra and the upper half of present-day La Unión. The current boundaries of the province set in March 1917 by virtue of Act No. 2683.

Apayao, officially the Province of Apayao (Ilocano: Probinsia ti Apayao; Itawit: Provinsiya ya Apayao; Isnag: Provinsia nga Apayao; Tagalog: Lalawigan ng Apayao), is a landlocked province in the Philippines in the Cordillera Administrative Region in Luzon. Kabugao serves as its capital. The provincial capitol and its associated offices are located at the New Government Center in Luna.

The province borders Cagayan to the north and east, Abra and Ilocos Norte to the west, and Kalinga to the south. Prior to 1995, Kalinga and Apayao comprised a single province named Kalinga-Apayao, which was partitioned to better service the needs of individual ethnic groups.

Kalinga (IPA: [ka'liŋɡa]), officially the Province of Kalinga (Ilocano: Probinsia ti Kalinga; Tagalog: Lalawigan ng Kalinga), is a landlocked province in the Philippines situated within the Cordillera Administrative Region in Luzon. Its capital (and largest city) is Tabuk and borders Mountain Province to the south, Abra to the west, Isabela to the east, Cagayan to the northeast, and Apayao to the north. Kalinga and Apayao are the result of the 1995 partitioning of the former province of Kalinga-Apayao which was seen to better service the respective needs of the various indigenous peoples in the area.

President Emilio Aguinaldo proclaimed Lubuagan town the seat of government for 73 days from March 6, 1900, to May 18, 1900, before finally fleeing to his last hideout in Palanan.

The Kalinga people (IPA: [ka'liŋɡa]) are an indigenous ethnic group whose ancestral domain is in the Cordillera Mountain Range of the northern Philippines. They are mainly found in Kalinga province which has an area of 3,282.58 sq. km. Some of them, however, already migrated to Mountain Province, Apayao, Cagayan, and Abra. The Kalinga numbered 163,167 as of 2010.

The Cordillera Central or Cordillera Range is a massive mountain range 320 kilometres (200 mi) long north–south and 118 kilometres (73 mi) east-west situated in the north-central part of the island of Luzon, in the Philippines. The mountain range encompasses all provinces of the Cordillera Administrative Region (Abra, Apayao, Benguet, Ifugao, Kalinga and Mountain Province), as well as portions of eastern Ilocos Norte, eastern Ilocos Sur, eastern La Union, northeastern Pangasinan, western Nueva Vizcaya, and western Cagayan.

To the north, the mountain range terminates at the northern shores of Luzon along the Babuyan Channel in Ilocos Norte and Cagayan provinces. At its southeastern part, the Central Cordillera is linked to the Sierra Madre Mountains, the longest mountain range in the country, through the Caraballo Mountains in Nueva Vizcaya province. During Spanish colonial period, the whole range was called Nueva Provincia (New Province).

Ilocos was a province in northern Luzon, Philippines that comprised the present-day provinces of Ilocos Norte, Ilocos Sur, parts of La Union, and Abra. In 1818, the province was disestablshed when it was split into Ilocos Norte and Ilocos Sur through a royal decree due to rapid population growth.