The Lohja Parish includes seven churches, the oldest of which, St. Lawrence's Church, was first mentioned in historical documents as early as 1382.

St. Lawrence's grey stone church is the third largest of Finland's medieval churches; only Turku Cathedral and Naantali's convent church are larger. However, Lohja is also home to stunning wooden churches exuding an old-world charm, such as Sammatti Church. Sammatti Church is one of Finland's oldest wooden churches still in use year-round.

The Chapel of All Saints, an Orthodox prayer house, is located in the Metsola cemetery. The building is a wooden chapel designed in the Karelian style.