It is the Catalan coastal mountain range, straddling Bages and Vallès Occidental, between the river Llobregat, in the west, and the River Ripoll, in the East. The nature reserve consists of two mountain ranges which give name and join the Estenalles. The highest peaks are La Mola (1103 m), which rises the Romanesque monastery of San Lorenzo, which gives its name to the bulk and Montcau (1056 m).