Rancagua is 85 km south of Santiago and the easiest connection is by train or bus. TerraSur runs frequent commuter trains from Santiago's Estación Central to the central Rancagua station — about an hour, fast, clean, comfortable. Long-distance buses serve the Rancagua terminal at all hours, with one company or another leaving Santiago's Terminal Sur every twenty minutes.
By car, the Ruta 5 (Panamericana) makes it a 75-minute drive in good traffic from Santiago. Coming from the south, all buses on the way to Concepción and Temuco call here.
There is no commercial airport. Santiago International is the practical gateway, with frequent transfers onward by bus or train.