Porte d'Ardon, Medieval gate in Laon, France.

The Porte d'Ardon is a medieval city gate in Laon with a double structure incorporating characteristic defensive features. The building displays typical elements of a fortified passage designed with multiple layers to protect the urban entrance.

The gate was documented from the 10th century onward and underwent major reconstruction during the 13th century. The original design included a drawbridge and multiple gates to secure passage through the fortification.

The gate served as a vital entry point for commerce and movement in the medieval city's fortification system. Today the structure still reflects its former role as a checkpoint controlling goods and people entering the urban area.

The gate is viewable from outside though some areas may be private and opening times should be respected. It is best seen during daylight hours when the architectural details are clearly visible.

The gate was preceded by a second structure built in 1741 and carved by Charles Hottin, whose pillars were topped with lions and representations of the arms of France; it was demolished in 1858. Beneath the passage ran a fountain and washhouses, covered over in the 19th century, of which only the washhouses remain.