According to the 2002 census of the National Statistics Institute, Mariquina spans an area of 1,320.5 km2 (510 sq mi) and has 18,223 inhabitants (9,361 men and 8,862 women).

[2] As a commune, Mariquina is a third-level administrative division of Chile administered by a municipal council, headed by an alcalde who is directly elected every four years.

The commune is represented in the Senate during the 2014–2022 period by Alfonso de Urresti (PS) and Ena von Baer (UDI) as part of the 16th senatorial constituency (Los Ríos Region).

[5] During the Mapuche uprising of 1881 most women of San José de la Mariquina were sent to the city of Valdivia as men prepared for hostilities.

[6] At the moment of the uprising it was even thought that rebels could reach Valdivia in the south if they succeeded in penetrating San José de la Mariquina.