The district was created under the 1916 Jones Law from the northern Luzon provinces of Batanes, Cagayan, Ilocos Norte, Ilocos Sur and Isabela.
Abra was added in 1917 upon its re-establishment as a regular province separate from Ilocos Sur.
[1] The district was represented by a total of six senators throughout its existence.
It was abolished in 1935 when a unicameral National Assembly was installed under a new constitution following the passage of the Tydings–McDuffie Act which established the Commonwealth of the Philippines.
It was last represented by Elpidio Quirino and Melecio Arranz of the Nacionalista Democrático.