It is around 10 km south of Ath. On 1 January 2006 the municipality had 13,347 inhabitants. The total area is 61.55 km², giving a population density of 217 inhabitants per km².
The history of the chateau is nebulous but the original construction of a fort or castle at the site is generally thought to date to the 14th century. This site was the seat of the barons of the Ligne family originating from Ligne in Hainault, a place about 8 kilometres from Beloeil. The earliest recorded baron of the House of Ligne was Fastré de Ligne, signatory to a charter dated 1047 and others of the name mentioned in a charter of Baudouin IV, count of Hainaut, dated to 1123.
- Beloeil on 28 June 1858. It used a Distribution postal code 8 with bars (before 1864), and 35 with points before 1874.
- Basècles on 21 April 1862. It used a Distribution postal code 126 with bars (before 1864), and 30 with points before 1874.
- Quevaucamps on 13 March 1876.
- Stambruges on 12 November 1888.
- Ramegnies-Chin on 27 June 1896.
^Catalogue Spécialisé des Oblitérations Belges, 1849-1910, NIPA, Antwerp, 1999.
^Liste des Numéros Postaux, Administration des Postes, Bruxelles 1969.
^Les numéros postaux belges en vigueur à partir du 1/10/1990, La Poste.
^ abc"Une fraternité internationale renforcée entre Belœil et ses entités jumelles". l'avenir. October 13, 2023. Retrieved June 2, 2024. ... des délégations étrangères étaient présentes le 30 septembre dernier pour le renouvellement des serments de jumelage entre Belœil, Crosne (France) et Schotten (Allemagne) à l'occasion de leur 60e anniversaire, ...