- The town of Gembloux is located at the northern tip of the Province of Namur. As result of the municipalities merger process that got underway between 1965 and 1977 the administrative entity of Gembloux now covers 12 districts: Beuzet, Bossière, Bothey, Corroy-le-Castle, Ernage, Gembloux, Grand-Manil, Grand-Leez, Isnes, Lonzée, Mazy and Sauvenière.
- Covering an area of nearly 10,000 ha Gembloux has a population of over 20,000 inhabitants. The altitude in Gembloux varies between 135 and 190 m. Gembloux is part of the Meuse basin, apart from the area to the west of the old Roman road from Bavay to Tongres, which is part of the Escaut basin.
- The Roman road crossing the Gembloux territory more or less follows the path taken by the ridge that separate these two basins. The River Orneau runs to Gembloux, from Grand-Leez located a few hundred meters from its source, as far Mazy before joining the River Sambre in Jemeppe.
- The Mazy section enjoys an international reputation for the black marble contained in its subsoil. Gembloux is a key communication node, where two highways cross: the N4 (Brussels -Namur) and the N29 (Charleroi-Tirlemont).
- The N93 (Namur-Nivelles) highway also crosses the Gembloux administrative district. The approach roads to the E411 (Brussels -Namur-Luxembourg) and E42 (Mons-Liège) motorways are located a few kilometres from the town. Gembloux is situated along the 161 railway line travelling from Brussels to Namur (Coast-Luxembourg route) and at the head of the 144 (Gembloux-Jemeppe-sur-Sambre) line.