Bonmont cistercian abbey, Cistercian monastery in Chéserex, Switzerland

Bonmont is a former Cistercian abbey in Chéserex, Vaud. Only the abbey church of Notre-Dame survives; the convent buildings are gone. The church, begun around 1131 and finished shortly before 1200, shows the transition from Romanesque to Gothic. A massive crossing tower replaced the roof turret in 1488. The 1738 Château de Bonmont stands on the site of the former monastery hospital.

Bonmont is first documented in 1123, when the lords of Divonne and Gingins granted it lands; its founding is placed between 1110 and 1120. In 1131, after Bernard of Clairvaux's visit, it joined the Cistercian order as Clairvaux's eighth daughter house, confirmed by a papal bull of 1132. Under Savoy protection in the 13th century it became one of the richest monasteries of the Lake Geneva region.

The name Bonmont comes from "de bonomonte", the form recorded in the first mention of 1123. The former abbey church, now owned by the canton of Vaud, is used for concerts and events through the Fondation de l'Abbaye de Bonmont, inaugurated on 23 June 1995. The conventual buildings are gone; Schloss Bonmont, built in 1738 on the site of the monastery hospital, stands south of the church and remains privately owned.

The former abbey church and the 1738 Bonmont castle stand within a golf course, 7 km west-northwest of Nyon above Chéserex. The convent buildings no longer exist, so the church is the main structure to visit; it was restored from 1982 and inaugurated on 23 June 1995. The castle is privately owned and not open to visitors.

The abbey church survived because it was put to farm use: it served as a wine store, grain loft, cheese dairy and bakery. Its Romanesque-Gothic crossing tower replaced a roof turret in 1488, and the building was restored only between 1982 and 1995.