Sights include the so-called "Cantina dei Santi" (Saints' cellar), which is a room which is the only remaining evidence of the ancient, powerful Benedictine monastery of S. Silano.

The town already existed in the 1st century AD, when it constituted a path that connected the Novara area with Valsesia; its name derives from "Romana Mansio".

The first historical document that mentions the town dates back to 882 when it - already belonging to the March of Ivrea - was donated by Charles the Fat to the bishop of Vercelli.

Another document, dating back to 1008, testifies to the presence of a Benedictine abbey dedicated to San Silano (or Saint Silvan) who must have played an important role in the town's economic development.

In 1198, the regency of Novara granted Romagnano the dignity of Burgus shortly afterward a castle was built there; of this construction, destroyed by French troops in 1477, the Praetorian Palace has been partially preserved, with an elegant rectangular tower (later raised in the second half of the 15th century).