According to data from the 2002 Census of Population and Housing, La Ligua had 31,987 inhabitants; of these, 24,214 (75.7%) lived in urban areas and 7,773 (24.3%) in rural areas. At that time, there were 16,079 men and 15,908 women.
As a commune, La Ligua is a third-level administrative division of Chile administered by a communal council, headed by an alcalde who is directly elected every four years. The 2008-2012 alcalde is Rodrigo Sánchez Villalobos. The communal council has the following members: