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

As of 2024, votes cast in the district also count towards the calculation of proportional representation ("plurinominal") deputies elected from the fourth region.

[2][3][a] Under the National Electoral Institute's 2022 districting plan, the 1st district's head town (cabecera distrital), where results from individual polling stations are gathered together and tallied, is the city of Huejutla in the extreme northeast of the state.

The 1st district covered fourteen municipalities in the same part of the state: 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's head town was at the state capital, Pachuca, and it comprised 12 municipalities.