Clairvaux, a village of France, in the department of Aube, on the left bank of the river Aube, 30 m. S. E. of Troyes; pop. about 2,000. It was the seat of a celebrated monastery dependent on the abbey of Citeaux, founded in 1114, in a wild glen, by Ungues, count of Champagne, and having St. Bernard as its first abbot. The foundation was increased by Thibaut, count of Champagne, and rich gifts were added by many kings of France, counts of Flanders, and other noble benefactors. The monks followed a rule of life which still further swelled their revenues. Timber was felled, saw mills were erected, the lands were drained and irrigated, farms were carefully tilled, tan yards, forges, oil mills, grain mills, fulling mills, and various hydraulic works were put in operation, cloth was woven, wool was spun, and the products not required for the use of the abbey were sold at Chutillon-sur-Seine, Bar-sur-Aube, etc. At the same time Clairvaux was a seat of learning, and was the abode at different periods of Pope Eugenius III., 15 cardinals, and many other dignitaries. In 1153 there were 700 monks within the abbey walls, and 76 other monasteries were affiliated to this.

In the 17th century it possessed nearly 50 villages, a vast number of farms, large vineyards, 60,000 acres of forest, 1,500 acres of fallow land, 4 metal forges and founderies, and an income of $120,000 a year; the number of its affiliated houses was 537, while the circuit of its walls exceeded that of the neighboring town of Chaumont. Its vast buildings have been converted into a prison (maison centrale de detention), where the convicts are employed in several trades, the proceeds of which defray the expenses of the establishment. It is one of the best regulated prisons in France. The abbey church, which contained the tombs of St. Bernard and of several kings and princes, was torn down to make room for the prison yard.