The town dates back nearly 3000 years when it was situated on the hills above the Granède.
By the second century A.D. the trade had collapsed from competition and subsequent invasions during the fourth and fifth centuries by barbarians saw the town relocate and settle to the opposite bank, changing its name to Amiliavum, then to Milhau en Rouergat (in the Millhau language), then to the French Millhau.
By the ninth century the town has grown and is the seat of a viguerie, a mediaeval administrative court, and a centre for the production of lambskin gloves. At this time the town is surrounded by ramparts. The tenth and eleventh centuries saw the creation of the Viscount of Millau and subsequently passed to the Counts of Provence, the Counts of Barcelona and eventually, in 1112, to the father of the future King of Aragon. In 1187, the King of Aragon grants him the seal and communal freedom of Provence by Consular Charter. A consulate was thus created, and was responsible for administering the city to raise taxes and to apply justice. In 1271, Millau passed to the crown of the kings of France.
In 1361, during the Hundred Years War, the city came under English rule. The return to peace in the fifteenth century gave the city a boost.
In the Middle Ages the town had one of the major mediaeval bridges across the river Tarn. It had 17 spans, but after one poorly maintained span fell in the 18th century, the bridge was mostly demolished. Just one span remains, with a mill that is now an art gallery, as testament to this significant trading route from north to south across pre-Renaissance France.
The Millau Viaduct was completed in 2004, eliminating traffic jams in the town centre. The town is now a tourist centre with one of the largest touring campsites in central France, benefiting from the attraction of the landscapes all around, and the architecturally acclaimed Millau viaduct. It is also a major centre for outdoor sporting activity.
It was designed by the English architect Lord Norman Foster and French structural engineer Michel Virlogeux. As of November 2018, it is the tallest bridge in the world, having a structural height of 343 metres (1,125 ft).
The Millau Viaduct is part of the highway from Paris to Béziers and Montpellier. It was built over three years. The bridge has been consistently ranked as one of the great engineering achievements of all time, and received the 2006 Outstanding Structure Award from the International Association for Bridge and Structural Engineering.
The highest pylons in the world: 244.96 metres (803 ft 8 in) and 221.05 metres (725 ft 3 in) in height, broke the world record previously held by the Kochertal Viaduct (Germany), which is 181 metres (594 ft) at its highest
Since opening in 2004, the deck height of Millau has been surpassed by several suspension bridges in China, including Sidu River Bridge, Baling River Bridge, and two spans (Beipan River Guanxing Highway Bridge and Beipan River Hukun Expressway Bridge) over the Beipan River.