Viladrau forms part of the district of Osona, in the province of Girona. The municipality has a surface area of 51 km2, and the village lies at 821 m.a.s.l. It can be found in the area where the Montseny hills come into contact with the Guilleies massif.
It is bordered to the north by Sant Sadurní d'Osormort, to the east by Espinelves and Arbúcies (Selva) - both of which, like Viladrau, form part of the administrative province of Girona-, to the south with the municipality of Montseny (Vallès Oriental), to the west with the municipalities of Seva and Taradell and to the north west with Sant Julià de Vilatorta.
The boundaries extend towards the northern slopes of Matagalls (1694 m) and Coll de Sant Marçal (1107 m), where the administrative boundaries of the districts of Osona, la Selva and el Vallès Oriental come together at a point known as Taula dels Tres Bisbes (Table of the Three Bishops), as far as Puig de Fàbregues (749 m) and Puig-l'agulla (810 m). There are several major peaks in this mountainous area, in the middle of the Montseny massif that is essentially formed of granite, including Puig Cornador (863 m), Puig Merli (988 m), Turó de la Tremoleda (1169 m), el Coll de Bordoriol (1096 m), located on the boundary with Arbúcies, Coll d'Ordials (1491 m), Puigsasucre (1108 m), Turó de Migdia (818 m) and Turó de les Cabrades (909 m), among others. The source of the Riera Major is formed on the northern slopes of Matagalls, which drains most of the water that flows through the municipality.