The Mechthildshäuser Gericht, first mentioned at the end of the 12th century, is an old court that belonged to a fortified court in the Kostheim village district. The name is thought to derive from Mechtildis, the wife of the last Gaugrafen in the Königssondergau, Udalrich III. The "Mechtildsstuhl" was the court of the Königssondergau, from which the Gaugrafen exercised high or blood jurisdiction in Carolingian times. At the end of the 13th century, the subjects of Nassau and thus the inhabitants of Wiesbaden also had to answer to the Mechthildshäuser court. The Wiesbaden Fronhof and its accessories were separated from this area; the Nassauers established their own court here. The Mechthildshausen court probably passed to the Lords of Eppstein before the middle of the 12th century.

The court district included the villages of Breckenheim, Delkenheim, Diedenbergen, Hochheim, Igstadt, Kostheim, Langenhain, Marxheim, Mechtildshausen, Medenbach, Nordenstadt, Wallau, Weilbach, Wicker and Wildsachsen. The Mechthildshausen court was responsible for all "neck court cases" that occurred in the respective villages. For other cases, criminal law was the responsibility of the mayor of the respective village. The district court bailiff appointed by the Lord of Eppstein presided over the court, assisted by the village aldermen.

From the 13th century onwards, Nassau and Eppstein became increasingly competitive with each other. The Counts of Nassau claimed that they owned the district court as an imperial fief and had leased it to the Lords of Eppstein. In 1418, Emperor Sigismund recognized Nassau's feudal sovereignty, but the Nassauers were unable to assert their rights. The Mechthildshausen court passed from the Lords of Eppstein to the Landgraves of Hesse in 1492.

The gallows of the Mechthildshausen court stood in the corner formed by the Landwehr and the historic "Steinern Straße", which is still marked on maps today. On an old Kostheim district map from 1741, this location is labeled "Am Gericht". In 1860, when model farming was introduced on the Mechtildshäuser Hof, all remains were removed.