Frasnes-lez-Anvaing is a Walloon municipality located in the Belgian province of Hainaut. On 1 January 2007 the municipality had 11,077 inhabitants. The total area is 112.44 km², giving a population density of 98.5 inhabitants per km². Since the beginning of 1977 it has been the center of the community that includes the commune of Frasnes-lez-Buissenal, and the former communes of Arc, Ainières, Wattripont, Forest, Anvaing, Buissenal, Moustier, Oeudeghien, Ellignies, Dergneau, Saint-Sauveur, Hacquegnies, and Herquegies.
In August 2012, the funeral of Countess Alix de Lannoy, mother of Stéphanie de Lannoy, was held in Frasnes, attended by members of the Luxembourg and Belgian royal families. 
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