Solid North

The term "Solid North" refers to the strong electoral support of northern Philippine provinces, particularly those of Ilocandia, to the family of President Ferdinand Marcos specifically, and other politicians of Ilocano descent and economic issues of affecting the Ilocanos in general, such as the tobacco industry. After the ouster of Marcos as a result of the People Power Revolution, electoral support for the Marcoses has waned but there is still significant support for them in the area.
The inclusion of some of the provinces in the Cordillera Administrative Region (CAR) in the Solid North has been questioned. While the lingua franca of the CAR is the Ilokano language, most of its residents are not Ilocanos and are referred to as the " Igorot" by Ilocanos and other lowlanders. These provinces all voted for Marcos while he was in power but have now mostly deviated from the regional voting patterns of the rest of northern Luzon. 
Prior to independence.
In the first national elections in 1907, the North became a stronghold of the Progresista Party, the primary opposition party to the Nacionalista Party at that time.
Third Republic presidential elections.
Before the election of Ferdinand Marcos in 1965, it was President Elpidio Quirino who consistently carried the Ilocano heartland in the presidential elections during which he was a candidate. Despite Ramon Magsaysay's landslide victory in the 1953 presidential election, Quirino still won in his home province of Ilocos Sur, as well as Ilocos Norte, Abra and La Union.
In the 1965 presidential election, Senator Ferdinand Marcos of the Nacionalista Party, from Ilocos Norte, faced the incumbent president Diosdado Macapagal of the Liberal Party, who hailed from Pampanga. Marcos successfully campaigned on the issues of graft, peace and order, and economic progress, although these had been staple campaign issues since independence. Marcos carried not only the Solid North, but most of Luzon as well, with Macapagal only carrying the provinces of Pampanga, Tarlac and Bataan.
While Marcos won an even larger mandate during his successful reelection bid in 1969, support from the Solid North was not as crucial in his victory. Pampanga and Antique in the Visayas were the only provinces that he did not win.
1986 snap presidential election.
Marcos eventually declared martial law and stayed in power until 1986, when he called for a "snap election". With his popularity declining after the assassination of Benigno Aquino Jr., Marcos relied heavily on support from the Solid North in the 1986 election, when he faced Aquino's widow, Corazon Aquino. Marcos depended on the Ilocos Region, described as "impregnable to the opposition", and on Eastern Visayas, the home region of his wife, First Lady Imelda Marcos. Marcos was eventually declared the winner but allegations of massive fraud erupted into the People Power Revolution which drove the Marcoses into exile and concluded with Aquino's ascension into the presidency.
Election maps.
In these maps, the provinces of the candidates where one won at least a plurality of votes is shaded.
The North in the presidential elections.
Key:
The North in the vice-presidential elections.
Key: