At 321 meters above sea level Fonte Gaia is situated at the highest elevation of all the fountains. It brings water from the zone north of the city along a ridge uninterrupted by valleys or depressions; it is considered to be "the queen of Sienese fountains" both for for its position, in the Piazza del Campo, and even more for its undoubted artistic merit. The ensemble, completed by Jacopo della Quercia between 1409 and 1419, has to be considered to be among the major expressions of Italian sculpture of the Quattrocento. The fountain that tourists admire today is, in fact, a copy by Tito Sarrocchi that replaced the original, destroyed by long centuries of exposure to the elements, in 1844. The fragmentary remains of Jacopo della Quercia's original masterpiece can be seen in the loggia of the Palazzo Comunale.
The surplus water from Fonte Gaia is sent through the more or less passable bottini in the valley below it until it reaches the fountains of Pantaneto, San Maurizio, Casato, and Pispini.