The area of what is now Thurgau was acquired as subject territories by the cantons of the Old Swiss Confederacy from the mid 15th century.

[5] In prehistoric times the lands of the canton were inhabited by people of the Pfyn culture along Lake Constance.

During Roman times the canton was part of the province Raetia until 450, when Alemanni settled on the lands.

The most important cities of Thurgovia in the early medieval period were Konstanz as the seat of the bishop and St. Gallen for the Abbey of Saint Gall.

The dukes of the House of Zähringen and the counts of the Kyburg family took over much of the land in the High Middle Ages.

In 1524, in an incident that resonated across Switzerland, local peasants occupied the cloister of Ittingen in the Thurgau, driving out monks, destroying documents, and devastating the wine-cellar.

tricolour); as the placement of a yellow (or) charge on white (argent) is a violation of heraldic principles, there have been suggestions to modify the design, including a 1938 suggestion to use a solid green field divided by a diagonal white line, but they were unsuccessful.

On March 26, 1806, Thurgau became the first state in the world to introduce compulsory smallpox vaccinations, by order of the cantonal councillor Jakob Christoph Scherb.

To the north the canton is bound by the Lake Constance across which lies Germany (Baden-Württemberg and Bavaria) and Austria (Vorarlberg).

[8] The historical population is given in the following table: Since January 2011, Thurgau has been divided into five districts which are named after their capitals.