Situated in the most part northern of Casola territory, Regnano preserve traces of historical architectures and popular traditions. Outside the suburb, it is possible to see the ruins of the castle built by the Longobard Guiterno in the XI century. In the 1185 Frederic I granted this fief to Pietro bishop of Luni, until his successor it surrendered it to the Malaspinas in 1202. In the suburb, the church of Saint Margherita shows some elements of its some elements of its original XII century protoromanesque structure.
According to a custom once diffused in Tuscany, in Regnano the “Maggio” is still sung, with dances and representations that recall legendary heroes.
Every year is celebrated the folckoric feast of the bread of Regnano, a typical product obtained from a paste of grain flour and boiled potatoes.