Rochefort, a small town of Belgium, situated on the Lomme, a tributary of the Lesse, in the S.E. of the province of Namur close to the Ardennes. Resident pop. (1904) 3068, which in July and August is doubled. It is of ancient origin, its position at the point where the route to St Hubert crossed that from Liege to Bouillon having made it at all times a place of some importance. The ruins of the old castle, which gave the place its name and a title to a long line of counts who had the right of coining their own money, still exist. This castle underwent many sieges and suffered much in the earlier wars, especially at the hands of Marshal de Chatillon in 1636. Rochefort is noted for its healthiness, and is a favourite place of residence. It also attracts every summer a large number of visitors and tourists, who visit it on account of the remarkable grottoes in its neighbourhood. One of these is situated in the town itself and is known by its name. This grotto contains six halls or chambers, the largest of which is called the Sabbat, and is remarkable for its great height. But the most famous are the grottoes of Han, situated three miles from Rochefort at Han sur Lesse. Here the river Lesse passes by a subterranean and undiscovered passage under the hill called Boerne or Boine. The endeavour to trace the course of the river led to the discovery of the grottoes, which consist of fifteen separate halls, connected by passages more or less short and emerging on the river in a dark and extensive cavern forming a sort of side creek or bay. Except in flood-time, when the exit has to be used, the entrance is near the point where the river disappears at what is called the gap or hole of Belvaux, and the exit is made by boat from the cavern last described, which leads out to the open river. A beautiful effect is afforded by the passage from the complete darkness of this cavern into the light. The finest stalactites are in the three halls called the Mysterieuses, the Vigneron and the Draperies. In the last-named is "the tomb," which looks as if chiselled out of white marble. The central hall - called the Salle d'Armes - is immense, and one of the river channels flows through it. Electric light has been introduced. Near Rochefort are the famous red marble quarries of St Remy, and the old Cistercian abbey of that name is now a Trappist seminary.