[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 second region.

[5] The district's head town (cabecera distrital), where results from individual polling stations are gathered together and tallied, is the city of Piedras Negras, Coahuila.

[1] Under the 2005 districting scheme, Coahuila's 1st district covered the municipalities of Acuña, Allende, Guerrero, Hidalgo, Jiménez, Morelos, Nava, Piedras Negras, Villa Unión and Zaragoza.

Between 1996 and 2005, the 1st district's territory was in the north and north-east region of the state and covered the municipalities of Acuña, Allende, Guerrero, Hidalgo, Jiménez, Morelos, Múzquiz, Nava, Piedras Negras, Villa Unión and Zaragoza.