Marengo Cave was found on 6 September 1883 by two children playing in a grove, who were drawn to an opening at the bottom of a sinkhole. Tours began within days. Not months, days: the cave was open to paying visitors almost immediately, and it has been running ever since, which makes it one of the longest continuously operating show caves in the United States.
The children were the Hiestands, and the accounts differ about why they went in. One version has them chasing a rabbit into the hole. The people connected with the cave denied the rabbit emphatically and put the discovery down to plain childish curiosity. There is a more prosaic explanation for the hole being there at all: the virgin timber had been cleared off that hillside shortly before, which increased runoff and gullying and is thought to have opened the sink.
They did not go far, certainly not beyond the reach of daylight, but far enough to report what they had seen.
Marengo is one of only four show caves in Indiana, and it was designated a National Natural Landmark in 1984. Its reputation rests on the density and preservation of its formations rather than on scale.
There are two walking tours covering different parts of the cave, and the operators also run cave simulator crawls and gemstone panning above ground, so it works as a family stop rather than a single walk-through. It sits at Marengo in Crawford County, close enough to Wyandotte Caves to make a day of two Indiana caves.
Other places on the map within a couple of hours.
