Heidelberg has a population of close to 130,000, of which 30,000 are students and teachers at the university. The city is bisected by the Neckar, a tributary of the Rhine. On one side is the old city, dating back to the seventeenth century, and on the other is the new one, built after World War Ⅱ. Heidelberg University is spread over both sides.
海城人口將近十三萬，海大師生職員佔了三萬；整個小城橫跨在萊茵河支流﹘﹘尼加河兩岸，一邊為十七世紀的老城，一邊是二次大戰後重建的新城，海大也零星散佈在新、舊兩方。