The cave is located at Seven Miles El Progresso in the Tapir Mountain Nature Reserve. The main cave system is about 3 mi (4.8 km) long and consists of a long river passage for approximately 2 mi (3.2 km), which ends at an upstream sump. A series of upper prehistoric passages continues another mile past the sump through massive breakdown boulders and giant rooms. The cave can be exited through a tight squeeze ending in a giant sink hole collapse in the jungle. The cave's upper passage is located about 1/3 of the way in from the lower entrance. Here 14 skeletal remains have been found, and numerous examples of ancient Maya pottery remain.