Brandenburg an der Havel is a town in Brandenburg, Germany, which served as the capital of the Margraviate of Brandenburg until replaced by Berlin in 1417.

With a population of 71,778 (as of 2010), it is located on the banks of the River Havel. The town of Brandenburg provided the name for the medieval Bishopric of Brandenburg, the Margraviate of Brandenburg, and the current state of Brandenburg. Today it is a small town compared to nearby Berlin, but it was the original nucleus of the former realms of Brandenburg and Prussia.

The Dominsel (Cathedral Island) is the historic heart of the town. Here stands its oldest edifice: the St. Peter and Paul Cathedral. Although construction began in the Romanesque style in 1165, it was completed as a Gothic cathedral during the 14th century. While the exterior is rather austere, the cathedral surprises the visitor with its sumptuous interior, especially the painted vault of the Bunte Kapelle (Coloured Chapel) and the Wagner organ (1725), one of the most famous Baroque organs in Germany.

The Katharinenkirche (St. Catherine's Church) built in 1401 in the Neustadt is an impressive example of northern German brick Gothic architecture. The Gotthardtkirche (St. Gotthardt's Church) was built of the same material just a few years later.

Another interesting building is the Altstädtisches Rathaus (Old Town Hall), a late Gothic brick building with stepped gables and an ornate portal. In front of it stands a 5.35m high statue of the knight Roland. Made of sandstone, the statue was erected in 1474 as a symbol of the town's independence.

There is also a part of Brandenburg's medieval city wall, with four preserved watchtowers: Steintorturm and Mühlentorturm (in the New Town), and Rathenower Torturm and Plauer Torturm (in the Old Town).

The Brandenburg Industrial Museum is an Anchor Point of ERIH, The European Route of Industrial Heritage. Brandenburg has its own theatre (Brandenburger Theater), a professional symphony orchestra (Brandenburger Symphoniker) and a wide range of local history and archaeology museums.