Bionaz is a comune sparso located in the North-Eastern Valpelline area of the Aosta Valley region in northwest Italy. The municipality covers an expansive territory of approximately 143 square kilometres (55 mi2).
The population of about 240 residents is dispersed across more than 20 small alpine villages and hamlets. Plan-de-Veyne serves as the main center and the capoluogo of the commune. Bionaz belongs to the Unité des communes valdôtaines du Grand-Combin.