The ancient origin of the town is attested by the numerous buildings in the area; according to the nuraghi density map, made by prof. Giovanni Lilliu, Genoni is among the areas with a density greater than 0.60 nuraghi per km², most of which can still be visited.
The elevated position of the Santu Antine hill, which Genoni is built on, has certainly attracted populations to settle in this area since ancient times.
Punic, Romans and most likely also the Vandals reached and then chose to live both in the Giara and on the Santu Antine hill; as the ruins found from the different eras allow us to hypothesize.
The walls of a Punic fortress on the hill, and, always at the top of the hill, the ruins of a Roman church dedicated to St. Helena and Constantine.
The villages of Santu Pedru, Mammuzzola, the spectacular Bruncu Suergiu and the sacred well of Sa corona arrubia.
The town reached large dimensions, probably because of its position out of the main transit ways.
The municipality of Genoni, part of the historical region of Sarcidano (central Sardinia), covers an area of about 44 km2, at altitudes between 300 and 600 m a.s.l. (Genoni, 447 m a.s.l.).
This territory, though not very extensive, shows a remarkable variety of geomorphological landscapes; due to a prolonged geological and paleogeographic evolution that has witnessed many important tectonic, volcanic, sedimentary and morphogenetic events that can be traced back about 300 million years ago, or at the end of the Paleozoic Era, but with a higher incidence in the last 25 million years or so.
This pleasant landscape is dominated by the characteristic isolated truncated cone block of Mount Santu Antine (591 m a.s.l.). It too, like the Giara, was carved in Miocene marl and bears at the top a residual limb of the Pliocene basalt.
The town of Genoni lies on the south-east side of this hill, in a beautiful and little known position, the one and the other together forming a picturesque landscape combination that is now a classic on the island and strongly characterizing this territory.
The territory has a long human presence attested by a considerable number of nuraghi, finds and a sacred well.
The name Giara, Sa Jara, probably derives from the Latin glarea (gravel), with reference to the widespread stoniness that characterizes the plateau surface.
The Pliocene basalt plateau of the Giara (500-600 m a.s.l.) surrounded by 11 municipalities, spreads to about 45 square kilometres of territory.
Steep dark lava rock cliffs, with its sometimes impetuous little waterfalls occasionally appearing, surround this vast plateau. Its surprisingly flat top is embellished with suggestive water stagnation Pauli (Tramatzu Pauli, Pauli Maiori, etc.) with their beautiful, glistening spring water buttercups blooms.
With its remarkable landscape and naturalistic value, the Giara has been included among the nine national parks established by Regional Law No. 31 of 1989