Sondrio, a N. province of Italy, in Lombardy, bounded N. W. and X. by Switzerland, N. E. by Tyrol, and S. by Brescia, Bergamo, and Como; area, 1,262 sq. m.; pop. in 1872, 111,-241. It includes the valleys of the Valtellina (Val Tellina), 45 m. long, and its continuation the former county of Bormio, and the valley of Chiavenna, and forms only one district. It is surrounded by branches of the Rhaetian Alps, including some of their highest summits, and the carriage roads over the Splugen, Bernina, and Stelvio passes, the last the highest of the Alpine roads, run through the province. The province abounds in picturesque localities. The principal river is the Adda. Excepting along the marshes near the lake of Como, the country is exceedingly fertile in grain and fruit, and especially in wine. The cheese is among the best in Lombardy. Iron and marble abound. The principal towns are Chiavenna, Bormio, and Sondrio, the capital, which has a population of about 5,000, and a fine cathedral. (See Valtellina).