Sønderborg is a Danish town located in the Region of Southern Denmark. It serves as the primary town and administrative seat of the Sønderborg Municipality, which has a total population of 74,123. The town itself has a population of 28,564.
The town functions as a regional center for trade, tourism, industry, and education. It serves as the headquarters for several industrial companies and joined the UNESCO Global Network of Learning Cities in 2016.