Pont Butin, Road bridge in Canton of Geneva, Switzerland

Pont Butin is a stone road and pedestrian bridge over the Rhone, 268.94 m long, with five 48 m arches topped by five smaller arcades. It links Aïre on the right bank to Petit-Lancy on the left, just downstream of the Rhone-Arve confluence. Its lower deck, 273 m long, 15 m wide and 12 m high, was built for a railway and is flanked by 30 arches of 6 m span.

A ferry, or traille, linked Aïre and Saint-Georges from 1782 about 500 m downstream, run by John Branchu from 1886 until 1927. David Butin, an iron merchant, left one million francs to the canton in 1913 for a bridge; work began in 1916 under Jules Jaeger and Richard Coray, a pier collapsed in 1924, and the bridge opened in 1926 at a cost of over 11 million francs.

The bridge is named after David Butin, a Geneva iron merchant (1834–1913) who left one million francs to fund a Rhone crossing between Lancy and Vernier; the Grand Council accepted the bequest on 21 June 1913. Until 1927 a cable-guided ferry, the traille, crossed about 500 m downstream between Aïre and Saint-Georges, run by local politician John Branchu, who also kept the Café du Bac at the top of the right-bank path.

You can cross this bridge on foot or drive across it, as it accommodates both types of movement. The structure is straightforward to access from both districts and remains in good working condition.

The lower deck, built for a railway line that was never laid, later housed Hispano-Suiza firing tests and then an aerodynamics and wind-tunnel laboratory (CMEFE). Nest boxes have been installed for brown long-eared bats, swifts and a pair of peregrine falcons observed in 2022.