|— Comune —|
|Comune di Grosio|
|Province||Province of Sondrio (SO)|
|- Total||127.0 km2 (49 sq mi)|
|Population (Dec. 2004)|
|- Density||37.7/km2 (97.7/sq mi)|
|Time zone||CET (UTC+1)|
|- Summer (DST)||CEST (UTC+2)|
Grosio is a comune (municipality) in the Province of Sondrio in the Italian region Lombardy, located about 130 km northeast of Milan and about 35 km northeast of Sondrio, on the border with Switzerland. As of 31 December 2004, it had a population of 4,790 and an area of 127.0 km².
The municipality of Grosio contains the frazioni (subdivisions, mainly villages and hamlets) Tiolo and Ravoledo.
On the hillside of Grosio lie the ruins of the S. Faustino and Visconti Venosta castles, the latter being mostly reconstructed and the former bearing only trace evidence of its former location save for a rebuilt chapel on the site. In the same location one can find petroglyphs dating back from 2200-1000 BCE.
At the center of Grosio is the 17th century church of San Giorgio. Inside, the single-nave church contains many frescoes by Cipriano Valorosa, the "Raphael of Valtellina". At the other end of town is the large parish church of San Giuseppe.