The town of Cinigiano developed around an ancient Medieval castle in the XII century on a hill relief overlooking the plain of Grosseto. With its 2000 inhabitants, it houses the church of Santa Maria delle Nevi, raised in the XV century, and the XVI-century church of San Michele Arcangelo.

In the Middle Ages, the territory of the current town was under the authority of Bernardino da Siena's descendants who were vassals belonging to the powerful counts Aldobrandeschi of the Santa Fiora branch.
In 1254, this family ceded the castle and of their properties to the Republic of Siena. Nevertheless, the Lords of Cinigliano's despotic and overbearing behaviour towards the local populations did not stop and their loyalty to Siena was other than real.
After some years, the Republic finally decided to intervene directly. In 1278, the Sienese thrust the last ruler of Cinigiano with the accuse of having assaulted a clergyman who was on his way to visit Pope John XXI in Viterbo. Yet, the intromission of a far more powerful seigniory impeded the town to start a period of political stability. In the XV century, the counts Guidi of Poppi and of Battifolle got possession of the castle.
Siena gained the territory of Cinigiano again in 1389 by paying a huge sum of money to the then ruler, the Count Francesco of Ugone of Battifolle, but a feudatory betrayed its faith once more. In effect, Francesco of Ugone continued tyrannizing in the territory regardless of the agreements, until 1404, when a population revolution chased him away and definitively consigned the town to Siena.
At its time, Siena caused the inclusion of Cinigiano's territory in the Tuscan Grand Duchy, after it definitively subjected to the Florentine Medici's power at the half of the XVI century. With the Grand Duchy rule by Pietro Leopoldo of Lorraine the town of Cinigiano was transferred from the province of Siena to the province of Grosseto in 1766. This new position was later confirmed by its annexation to the Kingdom of Italy in 1859.