Arch of Trajan, Ancient Roman triumphal arch in Canosa di Puglia, Italy.

The Arch of Trajan is a single-bay Roman arch built of brick, probably originally faced with marble, standing on the route of the Via Traiana in Canosa di Puglia. It is now partly buried but originally measured about 13 m high, 12 m wide and 5 m deep. Lesenes on the outer corners of the pylons and at the centre of their front faces once supported an entablature.

The structure was built in the 2nd century AD as part of the Via Traiana road system connecting Benevento and Brindisi. This route served as a major trade pathway through the Roman province of Apulia.

The arch displays Roman craftsmanship through its carved reliefs and classical column designs that reflect the building traditions of its era. These elements were typical features found in cities of that period.

The arch is accessible throughout the year and can be viewed from different positions around the structure. Walking around the monument allows visitors to examine the architectural details and stonework from various angles.

The arch was built of brick, not stone, and was probably coated in marble originally; it was restored several times in the 19th century and in 1911 with large amounts of modern reconstruction. Two marble reliefs from its decoration survive elsewhere: a fragment probably showing a Dacian, kept in the Museo diocesano in Trani, and a frieze fragment with a military scene, reused in Castel del Monte.