Tanglewood (Lenox, Mass.; www.bso.org)

The Boston Symphony Orchestra’s summer home and one of the great teaching festivals in America, Tanglewood is sprawled around a former estate in the Berkshires, centered on the house where the conductor Serge Koussevitzky’s possessions are preserved as if he were about to step through the door. Its alumni and faculty read like a Who’s Who of American music; in addition to its vaunted Shed, its chamber music pavilion is a jewel and its student orchestra one of the best in the country.

The Santa Fe Opera (Santa Fe, N.M.; www.santafeopera.org)

When John Crosby founded this company in the hills outside Santa Fe in 1957, the idea of an opera festival in the middle of nowhere seemed bizarre. Now, the Santa Fe Opera is the granddaddy of American opera festivals, offering top-flight productions and casts in five operas every summer, usually a couple of well-known works, something less-known, and, as often as not, a world or American premiere. Crosby’s successors, Richard Gaddes and Charles MacKay, have kept the festival’s tradition of commitment to new work and American singers but freed it slightly from the dominance of the lesser-known works of Richard Strauss (which Crosby helped bring into the repertoire).

Marlboro Chamber Music Festival (Marlboro, Vt.; www.marlboromusic.org)

Marlboro is primarily an experience for artists; on weekends, the audience is privileged to listen to the fruits of intense sessions of practice and exchange that go on during the week. The cream of a young crop of talent comes together here with some of the revered names in the field, meeting as equals in repertory they may not get a chance to do in their regular soloist lives, all shepherded by the festival’s co-directors, the renowned pianists Mitsuko Uchida and Richard Goode.

Aspen Music Festival and School (Aspen, Colo.; www.aspenmusicfestival.com)

The breathtaking Colorado landscape (at a literally breathtaking altitude) is the signature of this major teaching festival, which is a full-scale school on the one hand and a concert festival on the other. Aspen has gone through some upheaval in the past decade, most recently with the resignation of David Zinman as its music director, but an American conductor, Robert Spano, is taking over this year and launching a new beginning.

Spoleto Festival USA (Charleston, S.C.)

Founded by the composer Gian Carlo Menotti (“Amahl and the Night Visitors”) in 1977 as the American outpost of his festival in Spoleto, Italy — hence its name — Spoleto USA, no longer affiliated with its namesake, has become the leading American exponent of the European-style festival that brings in productions from around the world and juxtaposes chamber music and opera, theater and multimedia, the traditional and the avant-garde, taking over the city for a couple of weeks at the end of spring.

Also of note: Glimmerglass (Cooperstown, N.Y.; www.glimmerglass.org); Bard Summerscape/Bard Music Festival (Annandale-on-Hudson, N.Y.; www.bard.edu/bmf); Ojai Music Festival (Ojai, Calif.; www.ojaifestival.org); Ravinia Festival (Highland Park, Ill.; www.ravinia.org); Opera Theater of St. Louis (St. Louis; www.opera-stl.org)