The Hinboun area — sometimes called the Stone Forest — is a belt of dramatic limestone karst that rises out of central Laos roughly halfway between Vientiane and Savannakhet, about five to six hours' drive from either city. Towers and pinnacles of weathered stone stand over a landscape laced with rivers, sinkholes, and caves, and the whole region forms part of the larger Phu Hin Boun highlands. It is the kind of scenery that rewards slowing down: jagged grey rock, green river valleys, and villages tucked into the folds between the cliffs.
The standout attraction is the great river cave at Kong Lor, a seven-kilometre tunnel that the Nam Hin Bun River runs straight through. You travel it by long wooden boat in near-total darkness, headlamps picking out chambers so vast the beam never finds the ceiling, before emerging into a hidden valley village on the far side and turning back the way you came. Around the cave, the karst offers boat trips, cycling, and walking, all of it best arranged locally in the villages near the entrances.
This is a place for unhurried exploration rather than a quick stop. Distances are long, public transport is sparse, and most travellers reach the area with their own transport or a hired car and driver, often as a leg of a longer journey south toward Thakhek or Savannakhet. Allow at least a full day, and ideally an overnight stay, to see the caves properly and catch the dawn light on the cliffs.