The polis of Locri Epizephyrii was ruled following a typical Greek model. A strict conservative aristocracy exercised the power through the "one-thousand assembly", which was probably composed by all the citizens in charge of full political rights; also the population was divided in three tribes and thirty-six phratries.

At the heart of the Locrian organization there were Zaleukos' laws, which date back to the beginning of the VII century b.C. They were really "modern" laws for the age in which they were introduced; first of all they were written and so, as outlined by Strabo, they weren't kept in to the judges will. Moreover, even if some of them could seem somewhat cruel nowadays due to their retaliation roots, they doubtless marked a progress in civilization since allowed to avoid that kind of self-justice which was really common during that age.

Closed to any possible change, it was a really conservative legislation which gave to the city the chance to peacefully flourish and with little to none problems on the internal social front; that situation allowed the rulers of the city to concentrate all of their efforts on the thriving of the polis, on the expansion of the controlled territory and on the surveillance over the enemy populations outside the city boundaries.

To have a better idea of the Locrian society of that age it has to be pointed out the importance and the prestige of the rule of the women in the ancient Locri. Prestige which they owned not just for their strong appearance in the cults of the city but also for the large amounts of rights which they had according to the polis' laws (i.e.: they had all the inheritance rights, also the right to hand down the name of the family even after the death of every men of the family - husbands, sons, brothers etc. -). This peculiar situation, added to the tradition handed down by Polybius regarding the Locrian aristocracy (which, the historian, ascribed to the women and not to the men), led many modern experts to theorize the presence of an ancient matriarchal government in Locri (still another unsolved question due to the lack of evidences to confirm or to deny such theory).

Between the VII and the VI century b.C. the development of the polis was well underway; the city flourished with a strict and organized urban plan, and its sanctuaries with their cults were already well recognized almost everywhere in the Greek world. The internal situation was, as it has been already pointed out, ideal to start planning an expansion of the control over the territory around the city, even with the creation of some sub-colonies. That was necessary because, more than the need of control over a larger portion of territory, there was the risk that the great demographic increase of that age could harm the social equilibrium reached by the polis. Therefore, probably during the end of the VII century b.C., Medma (the modern Rosarno) and Hipponion (the modern Vibo Valentia) were founded on the Tyrrhenian coast.
 

By this time, with the foundation of these two sub-colonies, Locri Epizephyrii took the control of a large part of territory, spreading from the Ionian to the Tyrrhenian coasts and embracing the mountains between the two seas; this expansion created the conditions for the historical clashes against Kroton and Rhegion, cities which began to see in Locri Epizephyrii a dangerous problem for their future expansion.