Altona is the westernmost urban borough (Bezirk) of the German city state of Hamburg, on the right bank of the Elbe river. From 1640 to 1864 Altona was under the administration of the Danish monarchy. Altona was an independent city until 1937. In 2006 the population was 243,972.
The border of Altona to the south is the River Elbe, and across the river the state Lower Saxony and the boroughs Harburg and Hamburg-Mitte. To the east is the borough Hamburg-Mitte and to the north is the borough Eimsbüttel. The western border is to the state of Schleswig-Holstein. According to the statistical office Hamburg the area of Altona was in 2006 77.5 km² or 29.9 sq mi.