The 3rd federal electoral district of the State of Mexico () is one of the 300 electoral districts into which Mexico is divided for elections to the federal Chamber of Deputies and one of 40 such districts in the State of Mexico.
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 fifth region.
The current member for the district, elected in the 2024 general election, is Diana Castillo Gabino. Originally elected for the National Regeneration Movement (Morena), she switched allegiance to the Labour Party on 19 September 2024.
Under the 2023 districting plan adopted by the National Electoral Institute (INE), which is to be used for the 2024, 2027 and 2030 federal elections, the 3rd district covers 148 electoral precincts () across four municipalities in the north-west of the state:
The head town (), where results from individual polling stations are gathered together and tallied, is the city of Atlacomulco de Fabela.
The district reported a population of 415,863 in the 2020 Census. With Indigenous and Afrodescendent inhabitants accounting for over 65% of that number, the 3rd district is classified by the INE as an indigenous district.
Under the previous districting plans enacted by the INE and its predecessors, the 3rd district was situated as follows:
2005âÂÂ2022
1996âÂÂ2005
1978âÂÂ1996