The archaeological museum is housed in the building of the Town Hall, with its own entrance at the western side. At th beginning, the core of the museum was mostly the collection of inscriptions that Ioannis Kokkonis had gathered in 1834.
In 1898, archaeologist Chr. Tsountas discovered many important remains of the civilization of Cyclades, in Chalandriani and Kastri.
Today, an important number of these ancient findings, Hellenistic and Roman statues and inscriptions of Hermoupolis are exhibited in the museum.