[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 first region.

Under the National Electoral Institute's 2022 districting plan, which is to be used for the 2024, 2027 and 2030 federal elections,[4] Sonora's 7th district covers the seven municipalities in the state's south-east: Álamos, Benito Juárez, Etchojoa, Huatabampo, Navojoa, Quiriego and Rosario.

[5][6] The district's head town (cabecera distrital), where results from individual polling stations are gathered together and tallied, is the city of Navojoa.

[8] The districting scheme in force from 1978 to 1996 was the result of the 1977 electoral reforms, which increased the number of single-member seats in the Chamber of Deputies from 196 to 300.