In Blegny, 13,292 people live across 26.1 km². The average age is about 42, and 50.9% of residents are women. The population is 96.3% Belgian, 1.1% Italian, 0.8% French, 0.3% Spanish, 0.3% Dutch, 0.2% Turkish, 0.1% Romanian and 0.9% other nationalities. About 72% of residents own their homes. Average net income per person is €19,625 per year, and households have about 1.4 cars on average.
Houses dominate the local building stock, accounting for 92.1%, while apartment buildings account for 7.9%. By building type, 46.5% are open-type houses, farms or castles, 30.9% semi-closed houses, 12.6% closed houses, 7.8% buildings and flat blocks, 1.4% commercial houses and 0.8% other types. The average building age is around 1947; the average number of rooms is 5.9. There is currently 1 apartment for sale, listed at €285,000. The reported average price is also €285,000, with the listed range running from €285,000 to €285,000.
Blegny has access to the N604, N642, N653 and N667. The A3 / E25–E40–E42, linking Brussels, Leuven, Liège and Eupen and continuing towards Aachen, is about a 3-minute drive from the centre. The A25 / E25 towards Liège, Visé and Maastricht can be reached in about 6 minutes. TEC services include lines 107, 108, 109, 240 and 67, with routes linking locations such as Housse, Barchon, Herve, Saive, Liège and Visé. The nearest railway stations to the centre are Herstal, Wezet / Visé, Bressoux, Milmort and Vise-Frontiere.
There are 13 nurseries, 13 nursery schools and 13 primary schools in the municipality, but no secondary school. Ecole Fondamentale Libre Notre-Dame and Ecole Communale De Housse - Barchon are among the nursery schools; primary options include Ecole Fondamentale Communale De Mortier and Ecole Fondamentale Libre Saint-Joseph. For groceries, the town has 2 Carrefour stores, 1 Lidl and 1 Delhaize. There are no shared bicycles or shared cars available in the municipality, and no EV charging station is known there. Liège Airport is a 16-minute drive away, or 97 minutes by public transport.