Lariat Cave is a massive lava tube out on the high desert near American Falls, Idaho — one of the biggest caves in this volcanic corner of the state, in the same lava country that runs toward Craters of the Moon. For cavers and adventurous families, it's a genuinely impressive underground space: a huge, dark tunnel carved by ancient molten lava, cool and quiet no matter the weather above.

The cave is a classic lava tube, formed when the surface of a lava flow hardened while the molten rock beneath drained away, leaving a hollow passage behind. Lariat is notably large, and part of the fun is a loop near the back of the cave: the passage splits about two-thirds of the way in, letting you make a circuit rather than simply backtracking. It stays at a constant, cool temperature year-round, which has long made it popular — Boy Scout troops have used it as a sheltered campsite, much like the well-known Dead Horse Cave over near Gooding.

Getting there is the real challenge. The cave is reached via a rough dirt road off Crystal Ice Cave Road — the final stretch runs about 1.5 miles of deeply rutted dirt that is not suitable for low-clearance vehicles. In heavy rain or spring snowmelt it can turn to impassable mud, and it may be blocked by snow for much of the winter, with the cave entrance itself sometimes buried until the end of April. Plan your visit for dry summer or early-fall conditions, and bring a high-clearance or four-wheel-drive vehicle.

The cave sits in a fascinating volcanic landscape. This part of the Snake River Plain near American Falls is dotted with lava tubes and features, including the well-known Crystal Ice Cave along the same access road — a nearby cave famous for its ice formations. Exploring Lariat pairs naturally with a broader day poking around the volcanic country of southeastern Idaho, so bring good maps and plan your route, since these backroads are remote and lightly traveled.

Come prepared with proper caving gear. Bring at least two light sources per person (the cave is completely dark), wear a helmet and sturdy, closed-toe shoes for the rocky floor, and pack a warm layer, since it stays chilly inside even on the hottest day. This is remote country with little cell service, so don't go alone and tell someone your plans.

Tread lightly out here: pack out everything you bring, don't disturb any wildlife (including bats) using the cave, and leave the passages as you found them. For those willing to brave the road, Lariat Cave rewards you with one of the largest and most enjoyable lava-tube explorations in the American Falls area.