The peat-bog Mlynářská Slať (Mill Fen) lies about 3 km west of the village Modrava.

The peat-bog is 134 ha large, but only 32 ha is protected. The deepest point of the peat-bog is at 6 m and the supplies of the peat content is about 2.5 million cubic metres. The vegetation of peat-bogs and the most valuable part of the peat-bog are protected here.

The original reserve was established here in 1933. Now it is a protected area, which is a part of Zone I of the National Park Šumava (Bohemian Forest) and it is not open to the public.

The red marked path, which joins Modrava and Prášilské Jezero (Prášily Lake), leads along the northern border of the peat-bog.