The village is located in the Valle Belbo, in the southern part of Asti region, at 122 meters above sea level.
It is about 35 km from the provincial capital, Asti, and 25 km from Nizza Monferrato.
It is crossed by the Belbo torrent.
Castelnuovo Belbo adheres to the brotherhood pact among all the municipalities of Italy called Castelnuovo (26 in total).
The pact of brotherhood was signed in 2004 in the premises of the town hall of Castelnuovo Don Bosco.
The municipal offices of Castelnuovo Belbo are housed in a building of fine work dating back to the late nineteenth century.
Castelnuovo Belbo municipal offices are housed in a building of fine work dating back to the late nineteenth century.