Officially referred to as the Distrito Autónomo da Horta (Autonomous District of Horta) since 31 December 1940, it was originally established after the Liberal administrative reforms of Mouzinhos da Silveira on 28 March 1836.

During these reforms the Azores were redesignated dependencies of Portugal as the constitutionally-designated Ilhas Adjacentes (Adjacent Islands).

The district's creation resulted from the division of the Província Ocidental dos Açores (Western Province of the Azores), its seat in the district capital of Angra do Heroísmo, into two areas with the latter's seat in Horta.

[1] District autonomy was established during the Estado Novo regime of António de Oliveira Salazar in 1940.

The district of Horta included the western and the southern central islands of the Azores: Corvo, Flores, Faial and Pico.