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Oylat Cave and the Forests of İnegöl
Cultural

Oylat Cave and the Forests of İnegöl

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East of Bursa, in the mountainous country southeast of İnegöl, at the end of a canyon cut by the Oylat stream, there is a door that leads underground.

İnegöl, Bursa
Cultural
Radar Editör
October 15, 2026

About Trip

East of Bursa, in the mountainous country southeast of İnegöl, at the end of a canyon cut by the Oylat stream, there is a door that leads underground. Oylat Cave, with its dripstone pools and giant columns, is the best-known cave in Bursa; and it is not visited on its own but together with a forested valley, a stream and the steep rocks drawn by an old fault line. This is a nature trip you can make from the city and back in a day, one that cools you in summer and changes colour in autumn.

Getting there

According to the İnegöl District Governorate, Oylat is 27 kilometres from the district centre. The İnegöl article on Turkish Wikipedia gives the distance to Bursa as about 60 kilometres; the Hilmiye article writes that the village is 65 kilometres from Bursa and 20 from İnegöl. Those coming by car leave Bursa in the direction of Ankara, pass İnegöl and, as the Governorate describes it, turn towards Domaniç at the seventh kilometre of the Bursa-Eskişehir road; the road descends into the valley following the Oylat signs. The Culture Portal says the cave is about 17 kilometres in from the same junction, one kilometre south of Hilmiye village. For those using public transport, the Culture Portal writes that you can board İnegöl buses at Bursa's eastern bus garage on the Ankara road and reach the district and the spa; find out the time of the minibus from İnegöl towards Oylat from the district municipality or the bus station before you set out, since services thin out in the afternoon.

As the road climbs out of the İnegöl plain and bends south, the scenery changes. Turkish Wikipedia writes that İnegöl stands at an average height of 295 metres and that its surroundings are covered with forest; the reason the district is known today for furniture also lies in these forests. According to the same source, all kinds of wooden goods were made in İnegöl at first, and after the 1950s small workshops moved on to furniture making. So the road to Oylat passes through the forest that built the district's economy.

At the entrance to the valley

The first thing that catches the eye on arriving at Oylat is the steep rock mass at the entrance to the valley, known locally as Sivrikaya. According to the Governorate this formation is an old fault line and one of the places that must be seen. English Wikipedia writes that the cave too was formed on a significant east-west fault, inside a marble formation, and that the canyon walls rise to 450 to 500 metres at this point. The valley is narrow, the stream is fast, the slopes are covered with broadleaf trees; even in midsummer the bank of the stream stays in shade.

Up the valley are the Oylat hot springs. The Culture Portal writes that the spa has three sources, and the Governorate that the water temperature reaches 40.5 degrees. The spa facilities are not the subject of this trip, but they matter for describing where the cave is: the Governorate places the cave about two kilometres below the springs, between Hilmiye village and the springs, at the point where the Oylat canyon ends. The road that descends from the spa to the cave along the stream is a short and pleasant walk; it can also be driven.

Inside the cave

Oylat is, in Turkish Wikipedia's description, a horizontal fossil cave that has completed its formation, hanging as it were on the canyon slope on the western side of the Oylat stream. English Wikipedia reports that the main entrance is five to six metres above the canyon floor and that there are three more entrances higher up. On the length of the cave the sources give different figures: the Culture Portal, Turkish Wikipedia and the Governorate's culture page say 665 metres, while the Governorate's Oylat page says 750 metres. The difference most likely comes from the extent of the sections measured; both put the cave among the notable large caves of Turkey. The Governorate adds that there are 56 caves of various sizes in the district, 12 of them registered by the Ministry of Culture and Tourism; Oylat is the best known of this family.

The cave consists of two interconnected levels and two main sections. According to the Culture Portal, the first section, running from the entrance to the collapse chamber, is made up of narrow galleries; Turkish Wikipedia writes that these galleries are 15 metres high and two to five metres wide. Here are the hollows called giant kettles and the dripstone pools; point your light at the floor and the walls to see up close the marks water has left on the rock surface over centuries. The second section is a large collapse chamber: the big blocks and the giant dripstone forms, that is, the stalactites, stalagmites and columns, are here. Turkish Wikipedia reports that the chamber is 20 to 25 metres wide and 3 to 15 metres high, and that there is a height difference of 93 metres between the beginning and the end of the chamber; the Governorate adds wall and curtain dripstones to the list. According to English Wikipedia the cave was opened to tourism in 2006 and a visit takes about ninety minutes. Make sure your shoes do not slip; the floor is damp and the stairs and walkways can be wet.

The age of the cave and its discovery

English Wikipedia writes that the cave formed inside a marble formation about three million years old, in terrain dating from the Pliocene, and that fossils have been found inside. The same source adds that the cave has a winding, meandering plan, that its stalactites and stalagmites are colourful, and that alongside the large blocks the chamber also holds layers of gravel, sand and clay. These deposits have drawn the attention of scientists too; a study cited by Turkish Wikipedia, appearing with the date 2002 in the journal of the General Directorate of Mineral Research and Exploration, examines the sedimentology of the cave's sedimentary rocks. Wikipedia's infobox, however, gives 2004 as the year of discovery and 2006 as the year it opened to visitors; the 2002 study suggests the cave was known to scientists earlier. This formation, millions of years old, is still a fairly new address for travellers. English Wikipedia writes that domestic visitors come to the cave all year round, while foreign visitors mostly come between June and October.

The cave has its creatures too. According to Turkish Wikipedia, bats, millipedes, worms, butterflies and the small animals that live on guano shelter inside. Do not shine lights on the bats and do not shout; the cave is their home. Locals also call the cave the "Bursa cave"; the Governorate writes that this name comes from the belief that the cave was a secret road to Bursa. We know there is no such road; but as you walk through 665 metres of darkness it is not hard to understand where that belief came from.

A thermometer trip

The most interesting aspect of Oylat is the air that changes as you go deeper. The measurements quoted by the Culture Portal, taken in August 2000 according to Turkish Wikipedia, are as follows: in front of the cave 29 degrees and 47 percent humidity; at the entrance 19 degrees and 55 percent; in the narrow gallery 17 degrees and 78 percent; in the collapse chambers 14 degrees and 90 percent. So in midsummer there is a difference of fifteen degrees between outside and inside, and the humidity is almost like rain. English Wikipedia adds that the narrow passages are somewhat windy; you feel the air current between the levels on your face. Take a light jacket with you; even those who come to cool off in summer feel cold at the end of the chamber. It is said that the cave's humid air is good for respiratory illnesses; this is a folk belief, so consult your doctor for any visit with health in mind.

Forest and walking

The trip does not end when you leave the cave. The Governorate's Oylat page recommends coming to this valley "to walk breathing the clean air and listening to the birds, to watch the foam of the waterfalls". The road descending along the stream is the easiest option; walking towards Hilmiye village and back is an outing of an hour or two with little climbing. Keep in mind that the rocks are marble; they are slippery when wet. Do not go down into the stream bed, since the water rises quickly after rain.

Autumn is the most beautiful season in this valley. The broadleaf forest turns from yellow to red at the end of October, the stream clears and the crowds thin out. In spring the stream, fed by meltwater, is at its fullest; according to Turkish Wikipedia the Oylat springs are fed by the snow waters of Uludağ. In summer the cave is a cool refuge, while in the winter months you need to find out the snow and ice conditions on the road in advance.

Season and timing

Come early in the morning. A queue forms at the cave entrance at weekends and during the school half-term break; the Culture Portal lists Oylat among the places for the semester holiday. In the morning hours the valley is quieter, the birds louder, the stream bank cooler. Keep the afternoon for walking; the light on top of Sivrikaya at sunset is good for photographs. The cave's opening hours and entrance fee change; check the current information on the pages of İnegöl Municipality and the Governorate or on the spot.

Practical notes

Flat, non-slip shoes are essential for the cave visit; do not go in with sandals or heels. A small torch is useful, but do not shine it on the bats. Do not touch anything inside and do not take pieces of stone or dripstone; a centimetre of dripstone takes centuries to form. If you come with children, hold their hands on the stairs; the height difference between the chambers is 93 metres, so the walk involves more climbing and descending than you expect. It is not suitable for pushchairs.

There are few shops and restaurants in the valley; buy your water and food in İnegöl. Stopping in İnegöl on the way back to taste the meatballs that carry the district's name is the natural close to the trip; the Governorate and Turkish Wikipedia also mention İnegöl piyaz and şıra, the grape must drink, alongside the meatballs. Do not leave your litter in the valley; the cave and the stream are a natural area, so follow the rules set by the managing institution.

Oylat promises a day an hour away from the noise of the big city of Bursa, spent underground and inside the forest. A canyon that has broken its shell, a two-level cave and a forest that changes its leaves; all three together, in the same narrow valley.

Sources

Location - Oylat Cave and the Forests of İnegöl

Trip Info
Cityİnegöl, Bursa
TypeCultural
DateOctober 15, 2026
SourceRadar Editör
Radar TürkiyeAuthorRadar TürkiyeVisit SourceGet Directions