'Mountain garden'; Romagnol: Munt Giardêin) is one of the nine castelli of San Marino.

Montegiardino was added due to the last territorial expansion of San Marino, in 1463.

Due to its small size, it is the smallest subdivision of the country in population.

It is also the smallest country subdivision in the world by area.

[4][5] Singer and Sammarinese Eurovision entrant, Anita Simoncini is from Montegiardino.