In the end of the year 1860, similarly to other Papal States territories, Poggio Mirteto joined the Kingdom of Sardinia during the fast events which arranged the making of the Kingdom of Italy that happened in the next year.
In 1860, Poggio Mirteto, as part of the Papal States, joined the Kingdom of Sardinia during a period of political upheaval that ultimately led to the creation of the Kingdom of Italy in the following year.