Federal electoral districts of Mexico

The federal electoral districts (Spanish: distritos electorales federales) of Mexico are the 300 constituencies or electoral districts into which Mexico is divided for the purpose of federal elections. Each district returns one federal deputy (diputado), who sits in the Chamber of Deputies (Cámara de Diputados), the lower house of the Federal Congress. An additional 200 deputies are elected by proportional representation from the five electoral regions.

Electoral districts are identified by Roman numerals and by federal entity (state or the Federal District). 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 electoral census, and adjustments to the 1979 districts were made in 1996 and 2005.

Irrespective of population, no state may be represented by fewer than two electoral districts. This is the case with Baja California Sur (population: 512,000), Campeche (population: 755,000) and Colima (population: 568,000), which, as a result, return more senators than deputies to Congress. The states with the most electoral districts are the state of México (population: 14 million), with 40, and Veracruz (population: 7.1 million), with 21. The Federal District, with a population of 8.8 million, has 27.

On 11 February 2005, the Federal Electoral Institute (now the National Electoral Institute) established the districts to be used in the 2006 general election and the 2009 mid-term election, in accordance with the following criteria:

• Each district to belong to only one federal entity.
• Balanced distribution of population between districts.
• Presence of indigenous populations.
• Geographical continuity.
• Travel times.

Under this scheme, the current electoral districts are the following: