Lonquimay is a comuna and town in Chile administered by the municipality of Lonquimay. It is the terminus of a broad gauge railway which is often cited as the most practical railroad route over the Andes to Argentina. The line includes Las Raíces Tunnel, 4,563 m, Chile's longest, but has not yet been extended beyond Lonquimay. There is a missing link between Lonquimay and Zapala in Argentina.