The village of Castelnuovo Val di Cecina (Castrum Novum de Montanea in Latin) has Etruscan origins and gained importance in the Middle Ages when it became a fortified village of the Pisan republic on the borders of that of Siena. It is a hilly hill that is easily recognizable by its characteristic grape-like shape, which is intact and characteristic for its architectural homogeneity, narrow, tortuous stone paved streets, medieval gates, and glimpses on the valley. The parish church retains a beautiful crucifix dating back to the beginning of the 13th century, considered one of the most prestigious examples of the Sculptural Scriptural school. The San Rocco Oratory and the church of the village complete the itinerary of the sacred places.
The communal territory has a varied morphology that ranges from the Apennine environment to the Mediterranean scrub and then hills again with vineyards and olive groves. From Castelnuovo there are naturalistic trails that reach places of historical interest such as the bridge over the Pavone stream, or panoramic views from which you can admire the Valle del Cornia and the Gulf of Piombino.
Nearby are archaeological sites of the Etruscan and Roman period. Near the fortified village of Montecastelli, the Buca delle Fate, an Etruscan hypogeum of the 6th century BC and the remains of the copper mines, which were inactive since 1941, are noted. After a long excavation campaign, the Bagnone spa area is once again visited, a Hellenistic complex of the 3rd century BC from which water springs are still present at temperatures between 40 and 70 degrees. In the medieval hamlet of Leccia, there is the chapel dedicated to Madonna del Latte, whose celebration is celebrated on June 14 invoking its protection from hail.