(grēsŏnz', Fr. grēzôN'), Ger. Graubünden, Ital. Grigioni, Romansch Grischun, canton (1990 pop. 169,005), 2,746 sq mi (7,112 sq km), E Switzerland, bordering on Italy and Austria. Chur is the capital. The largest and most sparsely populated of the cantons, it is a region of Alpine peaks and glaciers, of forested highlands, and of fertile valleys. The Engadine Valley and the Swiss National Park, in the eastern part of the canton, attract large numbers of tourists. St. Moritz, Davos, and Arosa are the chief resorts. Industry is generally limited and is centered at Chur.
About a fourth of the population speaks Romansh, a Rhaetic-Romantic language; a smaller minority speaks Italian, and the rest, German. The Romansch-speakers live in the Vorderrhein valley (which they call Surselva) and in the Engadine. Italian-speakers inhabit the three southern prongs of the canton: the Val Mesolcida, the Val Bregaglia, and the Val di Poschiavo.
A part of Rhaetia under the Roman Empire, the territory preserved Roman laws and customs, although it nominally passed to the Ostrogoths (493) and to the Franks (537). In the 9th cent. the bishops of Chur began to attain prominence in the region. The bishops (after 1170 the prince-bishops) allied themselves with the rising power of the Hapsburgs. Their power, however, was checked and gradually broken by three local leagues founded between 1367 and 1436—the League of God's House, the Graubünden, or Gray League, and the League of Ten Jurisdictions. The three leagues, composed of communes and feudal lords, allied and joined with the Swiss Confederation. In 1512 they conquered the Valtellina from Milan.
Only part of the population accepted the Reformation (1524–26). In the Thirty Years War the country was rent by bloody strife between the Catholic party, siding with Spain and the Holy Roman emperor, and the Protestants, supporting Venice and France. With the Valtellina the chief bone of contention, the struggle was one of European importance. In 1799 the Grisons was forced by the French to enter the Helvetic Republic, and in 1803 it became a Swiss canton under Napoleon's Act of Mediation. The Valtellina was definitively lost at the Congress of Vienna (1815).