Ilocandia is the term given to the traditional homeland of the Ilocano people.
From the original western strip of Northern Luzon (now known as the Region 1 or Ilocos Region), Ilocandia has spread throughout the Cagayan Valley, Cordillera Administrative Region, and some parts of Central Luzon.
Although there are also a large number of Ilocanos in other parts of the Philippines like, Palawan and Mindanao, these are not considered to be a part of Ilocandia, as they are not part of the traditional Ilocano homeland.
Today, the first three regions of the Philippines (Region 1 or Ilocos Region, Region 2 or Cagayan Valley and Region 3 or Central Luzon) comprise the present-day Ilocandia. Although most of the residents of the Cordillera Administrative Region belong to another ethnic group (the Igorots), the predominance of the usage of Ilocano makes it also a part of the Ilocandia.
The northern portion of Ilocos Region (Ilocos Norte and Ilocos Sur) is the original Ilocano homeland. Originally composed of a single province known as Ilocos Province, it used to cover the western part of Northern Luzon. Today, the Ilocos Region includes four provinces, Pangasinan being the home of more than half of the region's population.
It is mistaken to assume that residents of Pangasinan are Ilocano speakers considering that according to the 2000 census, only 44% of Pangasinan population speak Ilocano. Pangasinan cannot even be considered as the original homeland of the Ilocano people since Ilocanos in Pangasinan are either migrants or descendants of migrants from the northern portion of Region 1 (Ilocos Norte and Ilocos Sur).