Chigualoco is an access point on the Estero Chigualoco, a small natural watercourse in the Coquimbo Region that flows just south of the lower reach of the río Choapa, draining a coastal basin of roughly 90 square kilometers before emptying at Bajos Chigualoco.

The stream's flow regime is strictly rain-fed, carrying water only during periods of coastal rainfall. The area around the estero includes Caleta Chigualoco, a working fishing harbor where local fishermen can be observed and fresh seafood is available.

The estero and its associated wetland are recognized as part of the natural and cultural heritage of the comuna de Los Vilos.