The Palazzo Comunale (or Town Hall) is one of the most important examples of medieval civic architecture in the Maremma.
Construction of the building began in the 13th century after the concession to Suvereto of the "Charta Liberatis" in 1201 by Ildebrandino VIII Aldobrandeschi, the feudal overlord. Following the concessions of 1201, Suvereto had become the first free comune in the northern Maremma and its inhabitants had acquired a series of significant rights, such as those to buy and sell property, and that of allowing new settlement within the walls. The layout of the building clearly reflects the administration of such varied necessities, one of the most important of which was the holding of courts to settle disputes between the citizens.
The Palazzo Comunale is topped by an ancient tower which now houses a clock, but once housed the bell that was rung to call an assembly of the Town Elders - the Anziani - and also served as a lookout within the community. The entrance to the building is preceded by a short and steep stairway under an open loggia supported on columns. This was the loggia dei giudici from which judgement and sentence was pronounced.
The structure we see today is an agglomerate of centuries of use. Originally there would have been an older nucleus, prevalently in wood and most likely similar to the pilaster house of Pisan type known in the early decades of the 13th century.
On the ground floor traces of the early circuit walls of the castle were found during exploratory excavations by the University of Siena. These date to the second half of the 12th century and demonstrate the extent of the noble dominions within the township, which centred on the castle keep.