Pont-Vieux d'Orthez, Medieval bridge in Orthez, France

The Pont-Vieux d'Orthez is a medieval stone bridge crossing the Gave de Pau river with four arches and a fortified central tower. The structure connects Orthez city center to the Départ district and displays the construction characteristics typical of its era.

Gaston VII of Béarn ordered the bridge built when he made Orthez his capital in the 13th century. A 1274 half-livre coin shows a single span flanked by two towers, likely with a wooden deck. The present four masonry arches may date to Gaston Fébus, resembling the Pont Valentré at Cahors. By 1589 only one tower remained, its upper part gone.

The bridge carries the name Pont Vieux, "old bridge", in French and Pont Vièlh in Occitan, the language once spoken in Béarn. It lies on the old vicomtal road that ran from the bridge of Haderne at Sault-de-Navailles to the bridge of Osserain and on toward Roncevaux, a route taken by pilgrims and travellers.

The bridge deck is 3.80 m wide between the parapets, rebuilt after the 1814 fighting. The roadway is open to pedestrians and vehicles, so walkers should keep to the edge. The riverbanks on both sides give access to the arches and the fortified tower.

In August 1569, Huguenot troops under Montgomery threw priests through an opening in the downstream parapet, still called the "priests' window", at the keystone of the main arch. In February 1814, 45 soldiers of Soult's rearguard held the tower for a day against Wellington's army; the assault destroyed all the parapets, rebuilt when the roadway was widened to 3.80 m.