Chart of Belgrade municipalities by population (2011)

Most of the municipalities are situated on the southern side of the Danube and Sava rivers, in the Šumadija region. Three municipalities (Zemun, Novi Beograd, and Surčin), are on the northern bank of the Sava, in the Syrmia region, and the municipality of Palilula, spanning the Danube, is in both the Šumadija and Banat regions.

Reference 1: Area (km2) and Population (2011).

Reference 2: Barajevo, Čukarica, Grocka, Lazarevac, Mladenovac, Novi Beograd, Obrenovac, Palilula, Rakovica, Savski Venac, Sopot, Stari Grad, Surčin, Voždovac, Vračar, Zemun, Zvezdara and Total.

Source: http://en.wikipedia.org/wiki/Belgrade