[1] It elects one deputy to the lower house of Congress for each three-year legislative session by means of the first-past-the-post system.

Votes cast in the district also count towards the calculation of proportional representation ("plurinominal") deputies elected from the first region.

[7] Under the 2005 plan, the district covered 13 municipalities: the 2022's scheme's 11, plus Benjamín Hill and Santa Ana.

[10][9] The districting scheme in force from 1978 to 1996 was the result of the 1977 electoral reforms, which increased the number of single-member seats in the Chamber of Deputies from 196 to 300.

[11] The 1st district had its head town at Magdalena de Kino and it covered 34 municipalities in the north of the state.