[1] 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.

[2][3] Michoacán lost its 12th district in the National Electoral Institute's 2022 redistricting process.

[1] Between 2017 and 2022, the district was located in the east of the state but shifted southwards compared to its 2022 configuration.

[10] The 3rd district's head town was at Zacapu and it covered eight municipalities in the centre of the state: