Belmont is a suburb located in the northern part of Mushroom City, the capital of the Mushroom Kingdom, making a prominent appearance in SMG4: Mario's Dangerous Delivery. It appears that this suburb is the closest to Peach's Castle, as seen when Mario and Luigi left the castle to head over to Frankie's school there. Meggy Spletzer moved there in SMG4: Meggy Moves In.
The name Belmont is actually a French word, made up of bel, meaning beautiful, and mont, meaning mountain. The name could be directly translated as 'beautiful mountain', due to it's location near the hills and mountains in the north, where Peach's Castle is located.
Besides, this could hint a possible legacy of the Mushroom Kingdom's colonisation due to the existence of the district, as probably it may had been a colony under France.
Belmont is the northern end of the Sunshire Highway, which links the suburb to Mushroom City. It is also the northern terminus of a subway line of the Super Bell Subway which connects it to Mushroom City via New Exton.