It is understood from historical artifacts which are found in archeological excavations in İnegöl that there has been a settlement in İnegöl and its surroundings since B.C. 3000.
Our region has been dominated by Hittites who firstly came to Anatolia in B.C. 19000 and 2000. In this land, which is understood to have hosted a settlement 5000 years ago, the Lydian, Persian and British people lived respectively. After the Roman Empire has been divided into two in A.D. 395, the region was left to the Eastern Roman Empire and then transferred to the Byzantium Empire.
The Byzantium domination continues in our region until the time İnegöl is conquered by Ottomans. The Seljuk Empire Alaaddin Keykubat gives Söğüt and surroundings to Ertuğrulgazi as winter quarters, and Domaniç and Ermeni Mountains as summer quarters. He has implemented the policy of getting along with neighboring Greek Beys and their feudal landlords and thus ensured that the clan got stronger morally and materially. After a while, Ertuğrul Gazi gets old and hands over his beylic to his son Osman Bey. Similarly, Osman Bey also continues the policy of getting along with feudal landlords in Bursa, Bilecik and surroundings.
Landlord Nicola one day learns that Osman Bey would attack the Angelacoma in a spring night and lays an ambush in a place called Ermeni Beli. Bay-Hoca, namely, Osman Bey''s young nephew dies in the war (1284-1286). Osman Bey feels very bad about the death of his brother attorney general''s son. Afterwards, he suddenly attacks the Kolça (Kulaca) Castle, which is very closely located to Angelacoma, with a troop of 300 soldiers and gets the castle. This incident is recorded as the first castle conquest in the Ottoman history (685 in Islamic calendar and 1286 in Gregorian calendar). Osman Bey never visits Angelacoma (İnegöl) and surroundings for approximately 14-15 years. Meanwhile, Osman Bey earns great achievements and gets the Karcahisar (İnönü Castle), Bilecik and Yarhisar Castles. A great many friends of feudal landlords of Angelacoma are erased from history.
Finally, he assigns Turgut Alp, who is a dear friend to him, to conquer Angelacoma. Turgut Alp conquers another castle, which was among the strongest ones of the time and which has caused a lot of work (699 in Islamic calendar and 1299 in Gregorian calendar). Osman Bey hands over the governance of İnegöl and surroundings to Turgut Alp. Afterwards, Turgut Alp governs İnegöl and surroundings for 36 years. His tomb is located in the cemetery of Turgut Alp (Genci) Village. İnegöl, which has been a township attached to the Bursa district during the government reform carried out in 1867, was attached to the Ertuğrul (Bilecik) district. The people have lived in İnegöl in peace and prosperity for many years and gained important investments thanks to grand vizier İshak Pasha (Prime Minister), among other Ottoman governors.
Our country is attacked by various states at the end of World War I. The Greek army organizes an attack against İnegöl for the first time to invade İnegöl and surroundings in July 8 – July 15, 1920. As a result of these attacks, 56 people die and 36 get injured. The Greek troops withdraw, depart from Bursa on the morning of January 6, 1921 and invade İnegöl''s surroundings. After getting a slap in the face in İnegöl''s surroundings on January 11, 1921, they leave all the regions that they have conquered and go back to the Bursa line. The 3rd Greek army corps departs from Bursa on March 24, 1921 again. They invade İnegöl and surroundings for the second time and proceed. They are defeated in İnönü again. They hardly pull themselves to the İnegöl-Bursa line on April 4, 1921. The Greek troops get into action for the third time on July 10, 1921. They are divided into two branches in İnegöl. The Greek troops depart in the direction of Cerrah and İnegöl on July 11, 1921 and do evil as much as they can in their surroundings.
The Greek remain in İnegöl and its surroundings for more than one year and establish a police station in Cerrah and Yenice to provide control. They follow the villages nearby from this location. The Greek who are defeated on September 12, 1922, put all settlements into fire before they withdraw. Finally, İnegöl and its surroundings are freed from the 26-day captivity on September 6, 1922. Our Bursa is saved on September 10, 1922. This is in a sense the victory sign and symbol of our national war which was made under the leadership of Mustafa Kemal ATATÜRK.