The patron of Poggio Mirteto is Saint Cajetan, celebrated on 7 August.
The population asked for the annual celebration of the self-liberation from the Papal States, giving rise to the Carnival of Poggio Mirteto, also known as Carnevalone poggiano, which reached its 157th edition in 2019. The festival, with its typical anticlerical tone and clear political connotation, is called Carnevalone Liberato and is held on the first Sunday of Lent, keeping the same spirit to this day. The town also holds the Cathedral of Santa Maria Assunta.
