The caves, one of the largest in the country, at an elevation of about 705 m (2,313 ft), distinctly exhibit a variety of speleothems ranging in size and irregularly shaped stalactites and stalagmites.

Quaternary deposits consist of red bed sediments, laterites, pediment fans, colluvium, alluvium and coastal sands.

[1] The caves in the reserved forest area basically host a variety of speleothems of various sizes and irregularly shaped stalactites and stalagmites.

The carbonate rocks are pure white, and coarsely crystalline and the deformed and banded marbles cover a triangular area of two km2 (0.77 sq mi); surrounded by diopside–scapolite–feldspar calc-granulites.

[8] The Gosthani River, which originates from these caves and flows between the solidified stalactites and stalagmites in the karstic limestones formation, is the cause for the development of the odd shapes of structures.

These deposits have developed into interesting forms and structures inside the caves such as Shiva–Parvati, Mother–Child, Rishi's beard, human brain, mushrooms, crocodile, temple, etc.

[10] The excavations carried out in the caves by the archeologists of the Andhra University, have unearthed stone tools of middle Paleolithic culture dating back 30,000 to 50,000 years, which confirm human habitation.

Petrographic analysis of a thin section has uncovered the presence of lithified structures and micrite, present as laminated to clotted with chocolate-brown blebs.

Laboratory observations with scanning electron microscope (SEM) have also confirmed the presence of calcified bacteria, micro-rods, and needle calcite.

Organic mats (yellow-orange in colour) are made up of mineralized filamentous bacteria, bacterial stalks, cells and sheaths.

[13] The caves are located in the Ananthagiri hills range of the Araku valley of the Alluri Sitharama Raju district in Andhra Pradesh.

The train journey over a distance of 100 km (62 mi) from the Vishkapatanam railway station passes through Eastern Ghats (hill) section), which has 30 tunnels en route.

[6] Guided tours for a day trip to the Borra Caves cover interesting attractions like the Tyada Railway Tunnel, Damuku View Point, Ananthagiri Coffee Plantation, Padmapuram Gardens and the Araku Valley.

The Andhra Pradesh State Tourism Department has installed 26 mercury, sodium vapor and halogen electric lamps, which provide views of the formations.