Electoral districts are identified by number and by federal entity (state or thecapital). The number of electoral districts was set at 300 in 1979, when the number of seats in the Chamber of Deputies was increased from 196. The demarcation of the districts depends on the results of the previous census, and adjustments to the 1979 districts were made in 1996, 2005, 2017 and 2022.
Irrespective of population, no state may be represented by fewer than two electoral districts. This is the case withBaja California Sur (population: 798,447),Campeche (population: 928,363) andColima (population: 731,391), which, as a result, return moresenators than deputies to Congress. The states with the most electoral districts are thestate of Mexico (population: 17.1 million), with 40, andVeracruz (population: 8.1 million), with 19. Mexico City, with a population of 9.2 million, has 22.
Each district to belong to only one federal entity.
Balanced distribution of population between districts.
Presence ofIndigenous andAfrodescendent inhabitants (districts with 40% or more of those populations are styled "indigenous districts" and receive special prerogatives).[a]
Geographical continuity.
Travel times.
The new districting scheme was published in theOfficial Journal on 20 February 2023.[2]