Tiergarten is a former borough of Berlin, since 2001 a part of the expanded borough Mitte. Before reunification, it was a part of West Berlin. It contains the neighbourhoods of Hansaviertel, Moabit and Tiergarten-Süd.
Among others, the Reichstag, the office of the German Chancellor and several embassies, as well as the residence of the German President, Schloss Bellevue, are located in Tiergarten. The Brandenburg Gate and the Potsdamer Platz are situated on its eastern border, which used to be the frontier between East and West Berlin.
Its name is derived from the Tiergarten Park, the biggest park in Berlin.