Burg Trausnitz im Tal, Medieval castle in Trausnitz, Germany.

Burg Trausnitz im Tal is a small three-winged castle on a pentagonal plan above the Pfreimd, with a square bergfried at the northwest corner beside the gate. Its high outer walls form the perimeter, enclosing a narrow inner courtyard. A ditch protects the western approach, and a pale tower with a steep pyramidal roof rises at the rear.

The castle was probably built in the mid-13th century by the lords of Waldthurn, ministeriales of the counts of Ortenburg-Murach, and was first documented in 1261. Around 1280 it passed to the Wittelsbachs. After the Battle of Mühldorf on 28 September 1322, Frederick the Fair of Austria was held prisoner here for 28 months. A fire damaged the castle in 1689; in 1830 the Karg-Bebenburg family sold it to King Ludwig I, and in 1837 the government restored the nearly ruined building.

The castle's name recalls the 28-month imprisonment of Frederick the Fair of Austria after the Battle of Mühldorf on 28 September 1322, the last great knightly battle on German soil. From 1926 the Burgfestspiele commemorated this episode with Fritz Hacker's play; a new piece, Gefangen in Trausnitz by Peter Klewitz, was staged in 1997.

The castle stands on a hill spur 448 m above sea level at the southern edge of Trausnitz, above the Pfreimd. The west access side is protected by a moat, and the high outer walls of the residential wings form the perimeter, so the inner courtyard is narrow and enclosed. The complex has served as a youth hostel since a full renovation carried out between 1993 and 1997.

The castle's fame rests on Frederick the Fair of Austria, held here for 28 months after his defeat at Mühldorf on 28 September 1322, the last great knightly battle on German soil. His jailer was Weichnand, the Wittelsbach viztum, a commoner trusted by Emperor Louis the Bavarian.