The Casa del Pilar de Esquina is a late-colonial house just off the Plaza de los Héroes, recognisable by the wooden corner pillar that gives it its name. The pillar-on-the-corner type was once common in Chilean colonial cities; this is one of the few survivors in central Chile.
It houses a small regional museum operated by the Museo Regional de Rancagua, with rooms furnished in 19th-century style and exhibits on the Rancagua battle and the rural life of the central valley. Combined with the Casa de la Cultura across the street, it forms the city's main museum complex.