During St. Michael's Days, the town comes alive and becomes the centre of gatherings, trade and entertainment. At the traditional goods and cattle fair, one can see or obtain almost everything: from various handmade products to domestic animals. An interesting culture and entertainment programme also takes place, and a person can find refreshments on every corner.

The central event occurs on September 29th, when Trilj celebrates the City Day and the Feast of its patron saint – St. Michael the Archangel. The traditional procession takes place in the city streets, and the St. Michael's Day Feast is at its peak.