Poggio Mirteto is a comune (municipality) is situated in the Tiber Valley area of the region of Latium, Italy.

According to Giuseppe Marocco's 1833 book [3] the name Poggio Mirteto means the "knoll with plenty of Myrtus plants" because in its territory there would be plenty of Myrtus plants (called mirto in Italian, which is where the adjective mirteto comes from) and the old town was built on a knoll which in Italian is translated with the toponym Poggio.

A Roman villa called "Bagni di Lucilla" is nearby in the suburb of San Valentino.

The city center is situated on a hill, which is around 250 meters above the sea level, by the left bank of the river Tevere in a fertile region, where pot-herbs, cereals, grapes and pastures are cultivated.

Opposite to Porta Farnese, at the other end of the square, there is the church of San Rocco (Saint Roch) which is up a staircase.

An old chimney made of bricks, now near the city center, is the most notable remainder of the former glassmaker Fajella which was built in the nineteenth century.

The castle of Castel San Pietro was the subject of a painting made by the Flemish painter Paul Bril in the early seventeen century.