POLLA, LA, a town of Naples, in the province of Principato Citra, on a hill at the entrance of the beautiful, fertile, and populous Val di Diano, 10 miles N.N.W. of La Sala. It has a number of churches and monastic institutions; and there are manufactures of silk and coarse woollen cloth. The Negro, which is here a considerable river, suddenly disappears at the foot of the hill on which the town is built, and flows underground for 2 miles as far as Pertosa. Pop. 5000.