1911 Encyclopædia Britannica/Tolfa
TOLFA, a town of the province of Rome, Italy, 10 m. E.N.E. of Civitavecchia by road, 1558 ft. above sea-level. Pop. (1901), 3956. It is the chief place in the Tolfa Mountains, an extinct volcanic group between Civitavecchia and the Lake of Bracciano. Vapours are emitted which deposit sulphur and alum, and some mining is carried on. The output of alum averages 4000 to 5000 tons a year, and is mostly exported from Civitavecchia.