The village of Saint-Geniez lies at the foot of the southern slopes of the Gouras and Trainon mountains in an anticline, or in ridges and folds, of black marlstone that has been heavily eroded to its core. Its agricultural land extends into Le Riou de Jabron valley at an altitude of over 1,000 metres.
It is not known when precisely the village was founded. The first mention of Sancto Genesio dates from 1202. Since the Middle Ages, the village has been associated with the figure of Saint Genies, Genest or Genès - a martyr, associated with the city of Arles, who lived at the end of the 4th century or the beginning of the 5th century and whose life was later recounted by Hilaire, Bishop of Arles. Genies is one of the oldest saints of Provence, whose veneration spread widely in the 5th century, to the point that Arles was then called Urbs Genesii.
The population of the Municipal District of Saint-Geniez has varied enormously over the centuries. Inhabited in 1471, following the great plague that had just ravaged the whole of Europe, the municipal district had 451 inhabitants in 1765. In 1851, the population reached the record figure of 515 inhabitants. Then the rural exodus began. The countryside of the high mountain lands experienced a real demographic "haemorrhage". In 1962, there were only 74 inhabitants.
Since 1990, the population has been around 50.