Aadorf is a municipality in the district of Münchwilen in the canton of Thurgau in Switzerland.

Graves from the Hallstatt period were discovered near Elgg and west of Bruggwingert.

The Bachwiesen archeological site has yielded scattered finds from the Bronze and Roman eras.

In 890, Count Udalrich IV established a clerical community that was affiliated with the church, for the care of his burial place.

During the Late Middle Ages the dominant landlord in Aadorf was the Abbey of St. Gallen.

The Thurgau Cantonal Constitution of 1831 placed all the monastery's assets under state control.

Two years later, 1850, they sold the monastery and chapel to the Planta family and the Tänikon parish church.

The monastery was sold in 1936 to Otto Zuber and in 1969 it was taken over by the new Eidgenosenschaft Forschungsanstalt für Betriebswirtschaft und Landtechnik (Swiss Federal Institute of Business and Agriculture).

[9] Aadorf has an area, as of 2017[update], of 19.94 square kilometers (7.70 sq mi).

[10] The municipality is located in the Frauenfeld district, between Winterthur and Wil (SG) along the Lützelmurg.

[12] The age distribution, as of 2009[update], in Aadorf is; 779 children or 9.8% of the population are between 0 and 9 years old and 1,041 teenagers or 13.0% are between 10 and 19.

[18] In the 2007 federal election the most popular party was the SVP which received 41.73% of the vote.

[19] The historical population is given in the following table:[4][20] The Agrotechnorama Tänikon and the former monastery church of St Bernhard are listed as Swiss heritage site of national significance.

[21] The former Cistercian monastery of Tänikon, which included the Church of St Bernhard, was first mentioned in 1247.

The monastery buildings eventually became a federal agricultural research facility, the Agrotechnorama Tänikon.

The former monastery church includes a marble pulpit and altar by Johann Josef Mosbrugger from 1830 to 1831.

[13] From the 2000 census[update], 3,014 or 41.3% were Roman Catholic, while 2,892 or 39.6% belonged to the Swiss Reformed Church.

[13] In 2014 the crime rate, of the over 200 crimes listed in the Swiss Criminal Code (running from murder, robbery and assault to accepting bribes and election fraud), in Aadorf was 33 per thousand residents.

The rate of violations of immigration, visa and work permit laws was 0.4 per thousand residents.

[26] The wettest month is June during which time Aadorf receives an average of 124 mm (4.9 in) of rain or snow.

The driest month of the year is February with an average of 73 mm (2.9 in) of precipitation over 10.0 days.