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, like other territories within the Papal States, joined the Kingdom of Sardinia during a time of significant political change that culminated in the formation of the Kingdom of Italy in the following year.