 After Piani di Praglia in Mele municipality it receives Rio di Fregeu from left hand assuming the name of "Stura".In this brief part of its course the Stura marks the border between the regions of Piemonte and Liguria, and the right part of its valley is encompassed in the Capanne di Marcarolo Natural Regional Park.Leaving the border it flows eastward in Liguria but, not faraway from Passo del Turchino, turns North and reaches Masone and Campo Ligure receiving from the right hand its main tributaries, Rio Vezzulla and Torrente Ponzema.