The comune stretches over sixty square kilometres across three provinces and passes through every possible height: it begins at sea level, with four kilometres of coast of dunes and white siliceous sand protected as a site of Community importance, and climbs to the eleven hundred metres of Elce della Vecchia, where there are holm oaks, beeches, oaks, chestnuts and silver fir. Inland lie the hamlet of Pietracupa and the waterfalls of the Assi torrent. The name is said to come from an older Guardacavalli, a guard post set on high ground, and indeed one of the coastal towers, at Vinciarello, is still called Torre Cavallara and bears the date 1485. The town was probably founded in the ninth century by people who went up into the heights to shelter from the Saracen raids.
Included in the fief of Stilo, Guardavalle shared its fortunes and passed from one master to another: Normans, Swabians, Angevins, then Aragonese, Spaniards, French and Bourbons. It became an autonomous comune only in 1799, by the act of general Championnet, the same French commander who in that same year made Ricadi independent of Tropea. Of that past there remain a dozen noble palaces — from Palazzo Criniti, dated 1492, to the nineteenth-century Falletti and Rispoli — the ruins of the basilica of San Carlo Borromeo, the Basilian monastery of Santa Maria at Marasà and the Galati mill of 1867. In the church of Maria Santissima del Carmine, of the seventeenth century, is kept instead the only still intact example of a frescoed dome of the Calabrian seventeenth century.