In the precordillera southeast of Pirque, Reserva Nacional Río Clarillo is a 10,185-hectare unit of glossy-leaved Mediterranean scrub woodland, plus denser gallery forest along the course of its namesake river, a Maipo tributary. While Conaf does not allow camping here, it does permit picnicking and hiking.
Two short nature trails have interpretive panels: the 1.2-kilometer Sendero Interpretativo Quebrada Jorquera and the 1.7-kilometer Sendero Interpretativo Aliven Mahuida, a more biologically diverse path. Conaf collects a US$5 per person admission charge.
Reserva Nacional Río Clarillo is 45 kilometers southeast of Santiago  and 18 kilometers from Pirque.