Before it reaches Florence, the valley of the river Arno is called superior. In the Pliocene the valley of the Arno was a vast lake; lately the valley was a zone of transit; in the Etruscan-Roman epoch it was crossed by the so-called Via Cassia Vetus which connected the territory of Arezzo to Fiesole.

Three municipalities lie on the left bank of the Arno, Incisa, Figline and Rignano: their territories are bounded between the river and the mountains of Chiant.

Figline Valdarno was founded toward the middle of the 12th century and reconstructed by the Florentine Republic in the latter half of the 14th century. In this period the town was given powerful walls which are still intact. This town was the birthplace of the humanist Marsilio Ficino (b. 1433), to whom the main square of the city is dedicated. The most important buildings in this square are a former hospital, the Spedale Serristori, with a magnificent 15th century loggia with frescoes by Niccolò Lapi, and the ancient collegiate church with a Museum of Sacred Art, which houses a splendid 14th century panel painting featuring the ‘Madonna and Child with Angels and Saints’.
Proceeding westwards, towards the Chianti region, we find the parish church of Gaville, dedicated to San Romolo, a good model of the romanesque style dating back to the 12-13th centuries; next to the church there is a small museum, dedicated to the Peasant civilization, with a large olive press dating back to the 17th century.

Moving on towards Florence you find Incisa in Val d’Arno, situated on a place where the river flows in a gorge which has been cut in the rock by the river itself. The landmark of the panorama is a tower (Torre del Castello), dating back to the 12-13th century,  overlooking the town itself and its surroundings. A major monument in the southern part of this region is the Chiesa del Vivaio, a 16th century church whose interior was completely refurbished in Baroque style. Near the 14th-century Oratorio del Crocefisso a Museum of Sacred Art has been recently set up. In the area of the castle there are the houses which belonged to the family of the poet Francesco Petrarca, who actually lived here for some years after being born in Arezzo 1304. North of the town of Incisa stands the former parish church of San Vito a Loppiano, one of the oldest churches of Valdarno, which is mentioned in documents of the year 1000 from local monasteries. Dating from the 12th century, it has three naves which are singular by being broader in extension than long, which gives the church a centralised plan feeling.

The Florentine Valdarno ends at the town of Rignano sull’Arno, in a scenary of entrancing castles and farmhouses among which one of the most impressive is the 18th- century Torre a Cona, rebuilt over a Medieval castle. The Castle of Volognano atop its vantage point is also medieval in origin while the beautiful defence tower called "Torre all'Isola" takes its name from having been built on an island in the middle of the river Arno when its bed was wider. The very ancient parish church of  San Leolino has three naves ending in apses. The church of S. Cristoforo in Perticaia, probably built around the 11th century, has a triptych attributed to Cenni di Francesco.
The municipal park of Fonte Santa is acknowledged as having significant environmental value  while in Rosano, which borders on Bagno a Ripoli, there is the Benedictine abbey of St. Mary, a convent established in the 8th century. The façade has a characteristic sixteenth century portal but the bell tower with its five tiers of windows is from the 12th  century.