Monte San Giorgio, Mountain summit in Piedmont, Italy.

Monte San Giorgio is a mountain summit in the Cottian Alps of Piedmont, rising to 837 meters. Its slopes are steep in places and made largely of peridotite, a rare rock type that gives the peak a markedly different appearance from the surrounding mountains.

Monte San Giorgio has served as a landmark for the plain below since the Bronze and Iron Ages, when a boulder-altar carved with 148 cup marks stood on its slopes. A small Romanesque church with three apses, dedicated to Saint George and older than the year 1000, was built on the summit in the Middle Ages; fourteenth-century frescoes there were still visible until the late nineteenth century. Excavations around the church have uncovered the remains of a monastic settlement. The shelter near the summit honours Lieutenant Lorenzo Nicola, awarded the Gold Medal of Military Valour, who died on the Russian front in 1943.

The summit church of San Giorgio predates the year 1000 and has three small apses; 14th-century frescoes, no longer visible, survived there until the late 19th century. Excavations around it found traces of a monastic settlement, now one of the FAI's Luoghi del Cuore. A white metal cross, lit at night and visible from Piossasco, stands beside it.

Several trails lead to the summit, including a hiking path from Tre Castelli and mountain bike routes on dirt roads. The slopes are steep in places, so solid footwear and appropriate gear are worth bringing along.

The peridotite rock found here comes from the Ultrabasic Lanzo massif and creates unusual chemical conditions in the soil. These conditions affect plant growth so strongly that the vegetation on this mountain looks noticeably different from that on the slopes nearby.