Heidelberg is a city located in the German state of Baden-Württemberg. It serves as the fifth-largest city within that state and ranks as the 51st-largest city in Germany, with a total population of approximately 163,000 residents.
The city is situated about 78 km (48 mi) south of Frankfurt. It is part of the Rhine-Neckar Metropolitan Region, which is centered in Mannheim. A significant portion of Heidelberg's population consists of students, who make up roughly a quarter of the city's inhabitants.