# 21st federal electoral district of the State of Mexico

The 21st federal electoral district of the State of Mexico (Spanish: Distrito electoral federal 21 del Estado de México) 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 21st district was created by the 1977 electoral reforms, which increased the number of single-member seats in the Chamber of Deputies from 196 to 300. Under that plan, the State of Mexico's seat allocation rose from 15 to 34. The new districts were first contended in the 1979 mid-term election.

## District territory

Under the National Electoral Institute's 2022 districting plan, which is to be used for the 2024, 2027 and 2030 federal elections, the 21st district is located in the state's eastern panhandle and covers 12 of its 125 municipalities:
* Amecameca, Atlautla, Ayapango, Cocotitlán, Ecatzingo, Juchitepec, Ozumba, Temamatla, Tenango del Aire, Tepetlixpa, Tlalmanalco and the eastern portion of Ixtapaluca.
The district's head town (cabecera distrital), where results from individual polling stations are gathered together and tallied, is the city of Amecameca de Juárez. In the 2020 Census, the district reported a total population of 410,835.

## Previous districting schemes

Evolution of electoral district numbers :
| | 1972 | 1978 | 1996 | 2005 | 2017 | 2022 |
| State of Mexico | 15 | 34 | 36 | 40 | 41 | 40 |
| Chamber of Deputies | 196 | 300 | 300 | 300 | 300 | 300 |
| Sources: |||||||
Under the previous districting plans enacted by the INE and its predecessors, the 21st district was situated as follows:

### 2017–2022

    Ten municipalities in the eastern panhandle: Amecameca, Atlautla, Ayapango, Ecatzingo, Juchitepec, Ozumba, Tenango del Aire, Tepetlixpa, Tlamanalco and the eastern portion of Ixtapaluca. The head town was at Amecameca de Juárez.

### 2005–2017

    A portion of the municipality of Naucalpan de Juárez.

### 1996–2005

    The northern, north-eastern and western parts of Naucalpan de Juárez.

### 1978–1996

    The municipalities of Acolman, Apaxco, Axapusco, Hueypoxtla, Jaltenco, Melchor Ocampo, Nextlalpan, Nopaltepec, San Martín de las Pirámides, Tecámac, Temascalapa, Teoloyucan, Teotihuacán, Tequixquiac, Tezoyuca, Tultepec and Zumpango, with its head town at Zumpango de Ocampo.

## Deputies returned to Congress

Twenty-first federal electoral district of the State of Mexico :
| Election | Deputy | Term | Legislature |
| 1979 | Alfredo Navarrete Romero | 1979–1982 | 51st Congress |
| 1982 | Hugo Díaz Thomé | 1982–1985 | 52nd Congress |
| 1985 | Pedro Zamora Ortiz | 1985–1988 | 53rd Congress |
| 1988 | Cecilio Barrera Reyes | 1988–1991 | 54th Congress |
| 1991 | Javier Barrios González | 1991–1994 | 55th Congress |
| 1994 | Leonel Domínguez Rivero | 1994–1997 | 56th Congress |
| 1997 | Héctor Flavio Valdez García | 1997–2000 | 57th Congress |
| 2000 | Moisés Alcalde Virgen | 2000–2003 | 58th Congress |
| 2003 | Manuel Gómez Morín Martínez del Río | 2003–2006 | 59th Congress |
| 2006 | Edgar Olvera Higuera María Eugenia Patiño Sánchez | 2006–2009 2009 | 60th Congress |
| 2009 | Rodrigo Reina Liceaga | 2009–2012 | 61st Congress |
| 2012 | Cristina Ruiz Sandoval | 2012–2015 | 62nd Congress |
| 2015 | Luis Gilberto Marrón Agustín Jaime Mauricio Rojas Silva | 2015–2018 2018 | 63rd Congress |
| 2018 | Graciela Sánchez Ortiz | 2018–2021 | 64th Congress |
| 2021 | Graciela Sánchez Ortiz | 2021–2024 | 65th Congress |
| 2024 | Iván Millán Contreras | 2024–2027 | 66th Congress |