europe, southern San Marino A country in the Apennine Mountains. It is a landlocked enclave, completely surrounded by Italy. San Marino is an enclave in Italy, on the border between the regioni of Emilia Romagna and Marche. Its topography is dominated by the Apennines mountain range. San Marino is divided into nine municipalities, known locally as Castelli (singular castello). LanguaL curation note: US FDA 1995 Code: SM Country San Marino A country in the Apennine Mountains. It is a landlocked enclave, completely surrounded by Italy. San Marino is an enclave in Italy, on the border between the regioni of Emilia Romagna and Marche. Its topography is dominated by the Apennines mountain range. San Marino is divided into nine municipalities, known locally as Castelli (singular castello). LanguaL curation note: US FDA 1995 Code: SM