The province of Pesaro and Urbino is a province in the Marche region of Italy. Its capital is the city of Pesaro. It also borders the state of San Marino. The province is surrounded by San Marino and Emilia Romagna in the north, Umbria and Tuscany in the west, Ancona in the south and the Adriatic Sea on the east. The province has an enclave of the Umbrian commune of Citta' di Castello named Monte Ruperto. The province is also known as "Riviera of Hills".