The commune has a surface of 1,453.8 km2 (561 sq mi)[3] and is bordered by Linares in the north, Retiro and Parral in the south, San Javier in the west and Colbún in the east.

[3] Most of what is today the commune of Longaví occupies what was formerly a vast Jesuit estate, The land had been granted to the Society of Jesus in 1639.

As a commune, Longaví 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 2012-2016 alcalde is Mario Briones Araice (PPD).The municipal council has the following members:[1][2] Within the electoral divisions of Chile, Longaví is represented in the Chamber of Deputies by Guillermo Ceroni (PPD) and Ignacio Urrutia (UDI) as part of the 40th electoral district, together with Retiro, Parral, Cauquenes, Pelluhue and Chanco.

The commune is represented in the Senate by Hernán Larraín UDI and Manuel Matta (PDC) as part of the 11th senatorial constituency (Maule-South).