The arch is 21 m high, 25.9 m wide and 7.4 m deep. It has three archways, the central one being 11.5 m high and 6.5 m wide, the lateral archways 7.4 m by 3.4 m each.
The arch spans the Via Triumphalis, the way taken by the emperors when they entered the city in triumph. This route started at the Campus Martius, led through the Circus Maximus and around the Palatine Hill; immediately after the Arch of Constantine, the procession would turn left at the Meta Sudans and march along the Via Sacra to the Forum Romanum and on to the Capitoline Hill, passing both the Arches of Titus and Septimius Severus. During the Middle Ages, the Arch of Constantine was incorporated into one of the family strongholds of ancient Rome. Works of restoration were first carried out in the 18th century; the last excavations have taken place in the late 1990s, just before the Great Jubilee of 2000. (Text based upon a Wikipedia article).