Hersonissos has developed due to tourism and, in just a few decades, has grown into the largest tourist resort in Crete.
Hersonissos has about 3,000 permanent inhabitants (2,981 in the 2001 census), but this number increases exponentially each summer, with the thousands of seasonal workers in tourism, and of course the hundreds of thousands of tourists who come to Hersonissos on holiday.
Hersonissos has been inhabited since the Minoan period (at least), due its good climate and the natural harbor formed east of Kastri Hill (in the location of the current port). Traces of the harbor and the Minoan settlements in Kastro and Anisaras have been found.
Later, in the Classic years, Hersonissos was an independent city, but not too strong.
In the Hellenistic times, Heronissos was the port of Lyttos city (close to today's Kastamonitsa). It was strong and had its own currency, with a symbol of a boat. From this period, a part of a temple dedicated to the goddess Vritomartis has been excavated over Kastri Hill, where many coins, vases and figurine parts have been extracted. Around it, you still can see parts of the walls that protected the hill. In Hersonissos, excavation revealed a cemetery of this period with a large number of pottery, jewelry and coins.
During the Roman period, Hersonissos flourished and its geographic position made it stronger than Lyttos. The theater of this period is not preserved today, as its inhabitants destroyed it in order to use the stones as building materials. Lastly, in the coastal road you will see the pyramidal structure with mosaics, called Sarakinos.
In early Christian times, Hersonissos continued to dominate the region. The most important finding of this period is the basilica on the hill Kastri. It was built in the 6th century and seems to have collapsed by an earthquake. The architecture was influenced by Syriac standards and was decorated with mosaics, some of which survive in good condition. The hill was surrounded by strong walls, traces of which exist. Another basilica has been found 2km east of the port. Part of the church is covered by the sea and you'll see mosaic floors, much nicer than those of Kastri.
During the Turkish occupation, the port was used to supply the Cretan rebels. Later, it was used for the exportation of local products (oil and carob).