According to the 2002 census of the National Statistics Institute, Quilleco spans an area of 1,121.8 km2 (433 sq mi) and has 10,428 inhabitants (5,378 men and 5,050 women).

[2] The principal economic activity of the area is agriculture with traditional crops such as beets and wheat in addition with vast plantations of exotic radiata pine and eucalyptus.

As a commune, Quilleco 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 municipal council has the following members:[1] Within the electoral divisions of Chile, Quilleco is represented in the Chamber of Deputies by Juan Lobos (UDI) and José Pérez (PRSD) as part of the 47th electoral district, together with Los Ángeles, Tucapel, Antuco, Santa Bárbara, Quilaco, Mulchén, Negrete, Nacimiento, San Rosendo, Laja and Alto Bío Bío.

The commune is represented in the Senate by Victor Pérez Varela (UDI) and Mariano Ruiz-Esquide Jara (PDC) as part of the 13th senatorial constituency (Biobío-Coast).