[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.

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

[6] The 3rd district was located in the extreme east of the state and covered much of the Lacandon Jungle.

It comprised the municipalities of Altamirano, Benemérito de las Américas, Chanal, Las Margaritas, Maravilla Tenejapa, Marqués de Comillas, Ocosingo and Oxchuc.

[9] The 3rd district had its head town at Comitán de Domínguez and it covered 15 municipalities.