Tønder (Southern Jutland: Tynne, Frisian: Tuner, German: Tondern) is a town in southwestern Southern Jutland, approx. 5 km. from the Danish-German border and has 7,581 inhabitants (2020). The city is located low on the transition between the heath plain and the marsh and is bounded by Vidå to the south. The country roads routes 8, 11 and 25 meet in Tønder.

Tønder is a modern school and business town with i.a. aluminum processing, photo laboratory, foundries and an active trading life combined with beautiful, old architecture. Today, the business community is dominated by a few large companies such as Norsk Hydro Aluminum, Pro Rengøring and Brdr. Hartmann A / S. In addition, the shoe group ECCO has a course and conference center near the city.

The nearest neighboring town is Møgeltønder, which is located 4 kilometers west of the town. Tønder has a day hospital. Tønder Station has several daily departures to Esbjerg and there are also daily departures to Niebüll / Germany with Arriva. Every year in August, the traditional Tønder Festival takes place, which especially features folk and jazz music. During the Christmas month, Tønder is especially known for its Christmas market and Det Gamle Apotek, which houses Scandinavia's largest Christmas exhibition.

In addition to Tønder Museum (now Kulturhistorie Tønder) with i.a. exhibition of architect Hans J. Wegner's furniture in the former water tower and the Art Museum in Tønder (formerly Sønderjyllands Kunstmuseum) there is a zeppelin and garrison museum north of the city. Cultural life is diverse with over 200 associations, of which the German minority also has a part.