Tournai is the largest municipality in Belgium, with an area of 215 square kilometres (km²), while Saint-Josse-Ten-Noode and Koekelberg are the smallest, with 1.2 km² each, according to data from the Belgian statistical office, Statbel.
Couvin is the second largest municipality in the country, with 207 km², and Antwerp the third largest, with 204 km².
Saint-Josse-Ten-Noode is Belgium’s most densely populated municipality, hosting 23,234 inhabitants per km².
The average population density in Belgium on 1 January 2022 was 377 inhabitants per km², up from 375 in 2021 and 372 in 2019.
Flanders has an average population density of 492 inhabitants per km², while Wallonia's is 217 per km² and Brussels-Capital Region 7,528 km².
The smallest municipality in Flanders is Herstappe (1.3 km²) ahead of Drogenbos (2.5 km²) and Messines (3.6 km²).
Saint-Nicolas, with an area of 6.9 km², is the smallest in Wallonia, ahead of Beyne-Heusay (7.3 km²) and Farciennes (10.5 km²).
Saint-Nicolas is also Wallonia's most densely populated commune, with 3,568 inhabitants per km², followed by Liège (2,845), Charleroi (1,966), Seraing (1,814) and Herstal (1,733 inhabitants/km²).
The differences between the extremes can also be very large, as in the case of population density, with a huge gap between Saint-Josse-Ten-Noode - 23,234-inhabitants per km² - and Daverdisse, in the province of Luxembourg, which is only 25 inhabitants per km².
The five most populated municipalities in the country are all part of the Brussels region: Saint-Josse-Ten-Noode, Saint-Gilles (19,274/km²), Koekelberg (18,633/km²), Schaerbeek (16,540/km²) and Molenbeek-Saint-Jean (16,241/km²).
The five least populated municipalities are all in Wallonia: Daverdisse (25 inhabitants/km²), Vresse-sur-Semois (25/km²), Sainte-Ode (27/km²), La Roche-en-Ardenne (28/km²) and Herbeumont (29/km²)
