Marcussen & Søn, also known as Marcussen and previously as Marcussen & Reuter, is a Danish firm of pipe organ builders. They were one of the first firms to go back to classical organ-building techniques, and have been producing mechanical-action organs since 1930. Aside from their many instruments in Denmark, they have built organs in northern Germany, Sweden, Finland, the Netherlands, Great Britain, South Africa, Japan, and the United States.

Aabenraa is a town in Southern Denmark, at the head of the Aabenraa Fjord, an arm of the Little Belt, 26 kilometres (16 mi) north of the Denmark–Germany border and 32 kilometres (20 mi) north of German town of Flensburg. It was the seat of Sønderjyllands Amt until 1 January 2007, when the Region of Southern Denmark was created as part of the 2007 Danish Municipal Reform. With a population of 16,685, Aabenraa is the largest town and the seat of the Aabenraa Municipality.