Freiburg Unterm Firstenstein, a town of Prussia, in the province of Silesia, on the Polsnitz, 35 m. W. S. W. of Breslau; pop. in 1871, 6,792. The principal establishment is a flax spinnery, but there are also manufactories of woollen and cotton goods and tobacco, distilleries, lime kilns, and tile works. The town is surrounded by walls, with three gates, and has three suburbs. In. the vicinity is the extensive domain of Furstenstein, with the old and modern castles of that name, the latter built in mediaeval style and celebrated for its picturesque situation.