The territory of Bollengo is partly on hill and partly on a plain. The territory of Bollengo is partly on hill and partly on a plain, it covers an overall area of 14,5 km² and it can be reached after a waòl along the Serra Morenica. Albiano d'Ivrea, Azeglio, Burolo, Ivrea, Magnano (Biella), Palazzo Canavese, Piverone and Torrazzo (Biella) are the adjacent Communes.
The etymology of the name could make reference to the word of Piedmont region boléngh and boia, that is a little ponds, wetland, in reference to the lake basins of the area. During the last years Bollengo has considerably developed, thanks to works of urbanization, to new businesses and initiatives for the inhabitants. Saint Eusebio is the patron and he is celebrated on the first Sunday of August.