Monterenzio is a town and comune in the province of Bologna (Emilia-Romagna, Italy).

The territory of the municipality rises on the ridge between the valleys of the Idice and Sillaro streams. The eleven rural units that make up the territory date back to the Pre-Napoleonic era. The Via Flaminia Minore road runs upon the crest and marks the watershed and the historic and cultural border between Emilia and Romagna.

The main town is located at about 34 km from Bologna, on the right side of the Idice and downstream of the community of Monterenzio that gave the name to the comune. In the past the town hall was located in Villa di Cassano and Ca' di Lavacchio, afterwards in Fiumetto, in 1880 and then from 1934 onwards in today's collocation.

Monterenzio might be identified in Monte Russi, mentioned for the first time in a decree from Emperor Otto III of 998 CE; a castrum (castle) or of Monte Renzoli was mentioned in a transaction of 1034. The first settlements date back to the Villanovian era, as some findings near Pizzano witness. Notably remarkable are an Etruscan-Celtic settlement discovered in the hamlet of Pianella di Monte Savino, nowadays still an object of excavations, dating back to the 4th century BCE that brought to light the presence of a tank for the gathering of water, certainly of public domain. The settlement reached its peak in the 3rd century BCE, whereas it should be followed by a swift period of decline due to the presence of Romans on the territory. A large necropolis has been found on top of Monte Tamburrino.