Ahrensburg is a town in the district of Stormarn, Schleswig-Holstein, Germany. It is located northeast of Hamburg and is part of the Hamburg Metropolitan Region. Its population is around 31,000. Schloss Ahrensburg, the town's symbol, is a Renaissance castle dating from 1595.

The Hamburg Metropolitan Region is a metropolitan area centred around the city of Hamburg in northern Germany, consisting of eight districts in the federal state of Lower Saxony, six districts in the state of Schleswig-Holstein and two districts in the state of Mecklenburg-Vorpommern along with the city-state of Hamburg itself. It covers an area of roughly 26,000 square kilometres (10,000 sq mi) and is home to more than 5.1 million inhabitants.