While the town of Teufen adopted the new protestant faith, Wonnenstein Friary remained Roman Catholic.

[3] In 1841 Teufen offered their new school building as a present to attract the government of the canton.

Of the rest of the land, 14% is settled (buildings or roads) and the remainder (0.8%) is non-productive (rivers, glaciers or mountains).

Most of the population (as of 2000[update]) speaks German (93.4%), with Italian being second most common ( 1.3%) and Spanish being third ( 0.9%).

[4] The historical population is given in the following table:[6] The Gmündertobel Bridge (shared with Stein, Appenzell), and the Wattbach Bridge (shared with Stein and St. Gallen) are listed as heritage sites of national significance.

The wettest month is June during which time Teufen receives an average of 191 mm (7.5 in) of precipitation.

The driest month of the year is February with an average of 88 mm (3.5 in) of precipitation over 15.1 days.

[8] Teufen is home to RC Tritec, a company that provides Tritium and other radioactive isotopes to industry.