From castra subdita to today's Castelli
The word "Castello" comes from the Latin phrase castra subdita, used in 1463 to designate the communities that passed under San Marino's control after being taken from the Malatesta of Rimini. The name outlived its military origin: when the ancient fortresses lost their defensive role, the term stayed as the label for San Marino's nine local jurisdictions.
Five of the nine Castelli (Serravalle, Faetano, Fiorentino, Domagnano and Montegiardino) joined the Republic in 1463, at the end of the war with Sigismondo Pandolfo Malatesta. Chiesanuova had already joined voluntarily in 1320. Acquaviva has belonged to the Republic since its origins, together with City of San Marino and Borgo Maggiore, historically known as Mercatale for the market held there.
«The Castelli are not miniature provinces: they are the communities the Republic recognises as its own, each with its traditions, coat of arms and direct link to the State.»
Local government
Each Castello is administered by a Giunta di Castello, made up of eight members in Castelli with more than 2,000 residents and six members in the smaller ones. The Giunta is chaired by the Capitano di Castello. It handles local services, territorial maintenance and the promotion of cultural, social and sporting activities that engage the community.
Elections take place every five years. All adult residents registered in the Castello's electoral roll are called to vote. At state level, coordination between the nine Giunte and the Republic's organs is entrusted to the Giunta di Castello Office.
Population and surface
| Castello | Residents | Surface | Distinctive trait |
|---|---|---|---|
| City of San Marino | 4,130 | 7.09 km² | The Republic's capital, historic centre and seat of the institutions, home to the Three Towers. |
| Borgo Maggiore | 6,966 | 9.01 km² | Historic Mercatale, a stop for Giuseppe Garibaldi in 1849 and the valley terminus of the cableway. |
| Serravalle | 11,237 | 10.53 km² | The most populous Castello, home to the San Marino Stadium and the clock tower. |
| Acquaviva | 2,144 | 4.86 km² | At the foot of Monte Cerreto, the place where tradition says Marinus found shelter and where the Placito Feretrano was drawn up. |
| Chiesanuova | 1,191 | 5.46 km² | Joined the Republic voluntarily in 1320, set along the valley of the Rio San Marino. |
| Domagnano | 3,608 | 6.62 km² | Settled since Roman times, former site of the Malatesta fortress of Monte Lupo. Its coat of arms shows a white wolf crowned by a tower. |
| Faetano | 1,190 | 7.75 km² | Named after the beech tree (Latin "fagus"), which appears in the coat of arms. A former Malatesta outpost annexed in 1463. |
| Fiorentino | 2,597 | 6.56 km² | Also known as Castellaccio, it was the closest Malatesta stronghold to the Republic's border. The name derives from "florente". |
| Montegiardino | 996 | 3.31 km² | The smallest and least populated Castello, set on rolling green hills echoed in its coat of arms. |
| Republic total | 34,059 | 61.19 km² | Data as of 31 March 2025 |
Source: Office of Informatics, Technology, Data and Statistics of the Republic of San Marino, Bollettino di Statistica - Q1 2025, Table 1.7.
Leonardo Casali, 2014
In 2014 the Philatelic and Numismatic Office issued a series of stamps dedicated to the nine Castelli. Each value portrays a defining feature: the bell tower of Borgo Maggiore with the cableway behind, the spring of Acquaviva, the church of Faetano, the Castellaccio of Fiorentino, the clock tower of Serravalle, the Casa del Castello of Chiesanuova, the Church of Domagnano, the bell tower of San Lorenzo in Montegiardino, and the Public Palace for the City of San Marino.
