FRESNILLO, a town of Mexico, in the state of Zacatecas, is situated 30 miles N.W. of Zacatecas, on a branch of the Santiago river, in the plain which divides the mountains of Santa Cruz and Deganos from the Zacatecas range. It is well built, and its streets are clean and regular. The country in the immediate neighbourhood is pretty and fertile, and maize and wheat are cultivated. Fresnillo is noted chiefly for its silver mines situated at the adjacent knoll of Proaño. They were discovered in 1569, and for a long period have been the most productive in the country, the annual yield averaging more than £500,000. A school of mines was founded in 1853. Population about 15,000.