The original name of Oranienburg was Bötzow. The town was founded in the 12th century and was first mentioned in 1216. Albert the Bear is believed to have ordered the construction of a castle on the banks of the Havel. Around the castle there was a settlement of traders and craftsmen.
In 1646 Friedrich Wilhelm I of Brandenburg was married with Louise Henriette of Orange-Nassau (German: Oranien-Nassau). She was so attracted by the town of Bölkow, that her husband presented her the entire region. The princess ordered to build a new castle in Dutch style and called it Oranienburg. In 1653 the town of Bölkow was renamed to Oranienburg.
In the Nazi era Oranienburg was made a showplace of terror. The first German concentration camp was built there in 1933; in 1935 another camp was established in the quarter of Sachsenhausen. While the first one was dissolved as early as 1934, the camp of Sachsenhausen continued to exist; 100,000 people were killed in Sachsenhausen until the liberation of the camp by the Red Army in 1945.