Strabo (XII, 4, 7) mentions a Hellenistic town, Bithynium (Greek: Βιθύνιον), celebrated for its pastures and cheese, which according to Pausanias (VIII, 9) was founded by Arcadians from Mantinea.

[4][5] In the Ancient Roman era, as is shown by its coins, the town was commonly called Claudiopolis (Κλαυδιούπολις) after Emperor Claudius.

Emperor Theodosius II (408-50) made it the capital of a new province, formed out of Bithynia and Paphlagonia, and called by him Honorias in honour of his younger son and successor Honorius.

After the Battle of Manzikert in which the Byzantines suffered a defeat at the hands of the Seljuks, Turkmens migrating west settled the city in the 11th century and it was referred to as Boli, Turkicized short for the Greek Polis 'city'.

In 1325, the town was conquered by the Ottoman Empire under Orhan, becoming known under the present Turkish name - sometimes called Bolou or Boli.

It appears as such in the Notitiae Episcopatuum of Pseudo-Epiphanius of about 640 and in that of Byzantine Emperor Leo VI the Wise of the early 10th century, ranking sixteenth viz.

[11] The Kadı Mosque is perhaps the best example of classical Ottoman architecture in the city, having been built in 1499 and having its entrance embroidered with ornate kündekari works.

[16] Local specialities include a sweet made of hazelnuts (which grow in abundance here) and an eau-de-cologne with the scent of grass.

One feature of Bolu dear to the local people is the soft spring water (kökez suyu) obtained from fountains in the town.

Students from the university and soldiers based in Bolu make an important contribution to the local economy, which traditionally depended on forestry and handicrafts.

Unlike the low-lying, sheltered city center, many parts of the province, like Gerede, have a colder humid continental climate (Dfb/Dcb), due to cold winters.