Extending across the central valley of Chile, the province has a considerable area devoted to traditional agriculture and wine-growing.

The principal towns are San Fernando, the provincial capital,[4] Santa Cruz, Chimbarongo, Nancagua and Palmilla.

San Fernando is one of the several towns founded in 1742 by the governor-general José Antonio Manso de Velasco,[4] and it had a population of 64,000 in 2002.

As a province, Colchagua is a second-level administrative division of Chile, governed by a provincial delegate who is appointed by the president.

The state central railway (EFE) from Santiago to the south crosses the province and has a regular stop in San Fernando.