The square is located on the site formerly occupied by the Stadium of Domitian, built in the year 85 and subjected to restorations during the third century under the reign of Emperor Alexander Severus. This stadium, originally known as Circus Agonalis, eventually changed its name from "in agone" to "navone" and then to "navona". Its orientation was north-south, just like today's square, and it had impressive dimensions: 276 meters long by 106 meters wide, and could accommodate an audience of up to 30,000 people. Some remains of the original structure can still be seen to the north of the plaza. This stadium was the scene of the Greek athletic games, which together with the musical and equestrian events formed the Capitolinum Contest in honor of the god Jupiter.

Throughout the Middle Ages, there was a gradual fragmentation of the ruins of the ancient stadium, with the construction of buildings that were initially oriented towards the surrounding streets, but then turned towards the space where the stadium was located.

The square acquired its character as a public space at the end of the 15th century, during the papacy of Sixtus V, a prominent urban planner of Rome, when the market that was previously held on the Capitoline Hill was moved here. Under the patronage of Pope Innocent X, a member of the Pamphili family, the square adopted its present Baroque design, including the construction of fountains and the church of St. Agnes in Agona, as well as the Palazzo Pamphili. During the Jubilee of 1650, the Pope celebrated Easter mass in this square, attracting crowds and making the square a symbol of the baroque style in Rome.

The market that used to be held in this square was moved to Campo de' Fiori in 1869. Over the years, the square has been the scene of theatrical performances and horse races. Since 1652, thanks to the patronage of the Pamphili family, every Saturday and Sunday in August, the central part of the square was flooded by closing the drains of the three fountains, creating what was known as the "Lake of Piazza Navona". This tradition was discontinued in 1866.

The elongated shape of the square reflects the track of the ancient Stadium of Domitian, maintaining its original dimensions and even the curvature in the northern area, while the surrounding buildings stand on what used to be the stands of the stadium.

The most outstanding element of the square are the three imposing fountains adorned with sculptures that stretch along it. The most prominent is the Fountain of the Four Rivers (Fontana dei Quattro Fiumi) in the center, a Baroque work commissioned by Pope Innocent X to Gian Lorenzo Bernini between 1648 and 1651. This fountain represents the four great rivers known at the time: the Nile (Africa), the Ganges (Asia), the Danube (Europe) and the Rio de la Plata (America). At the top of the fountain is the obelisk of Domitian, which measures 17.6 meters and was brought from the Majentian circus on the Appian Way.

The other two fountains are at the ends of the square: at the north end, the Fontana di Nettuno, designed by Giacomo della Porta, although the statues of Neptune and the nereids are from the nineteenth century, and at the south end, the Fontana del Moro, also designed by della Porta and later adorned with the sculpture of the Moor and the dolphin, created by Bernini.