San Marino, officially the Republic of San Marino and also known as the Most Serene Republic of San Marino, is the oldest existing representative republic and the European state with the smallest population, apart from Vatican City. It is surrounded by Italy. Located on the northeastern side of the Apennine Mountains, it is the fifth-smallest country in the world, with a land area of just over 61 km2 and a population of 33,642, as of 2023.