Graham Nash, Stephen Stills, David Crosby. Anyone who listened to Top 40 radio in the mid- to late ’60s heard their voices even before they became the supergroup known as Crosby, Stills, & Nash.

Crosby flew high with the Byrds, the talent-packed Los Angeles group that released the hits “Mr. Tambourine Man,” “Turn! Turn! Turn!” and “Eight Miles High.”

Nash was a member of the harmonizing Hollies. One of the many British invasion groups, the Hollies’ stateside hits included “Bus Stop,” “On a Carousel” and “Carrie Anne.”

Stills composed and sang the biggest hit his short-lived group, Buffalo Springfield, had, a haunting protest song called “For What It’s Worth.”

Stills was the dominant voice in Buffalo Springfield, but Nash and Crosby were more supporting players in the Byrds and Hollies. In Crosby, Stills, & Nash, however, the trio that sprang from a Laurel Canyon jam session, Nash and Crosby bloomed, sharing frontman status with Stills.

Crosby, Stills, & Nash’s self-titled album debut, released in June 1969, was a hit, as was the group’s debut single, “Suite: Judy Blue Eyes.”

The trio performed “Judy Blue Eyes” 45 years ago this month at the Woodstock Music & Art Fair. Making its concert debut at Woodstock, the original CSN was joined by a new, fourth member that night, Stills’ former Buffalo Springfield band mate, Neil Young.

CSN’s uniquely close vocal harmonies plus songs destined to be classics of the future — including Stills’ “Judy Blue Eyes,” Crosby’s “Long Time Gone,” Nash’s “Teach Your Children” and the majestic Crosby-Stills collaboration, “Wooden Ships” — ensured the trio’s lasting impact.

Crosby, Stills, & Nash’s 2014 summer-fall tour, which includes the group’s Saturday, Aug. 23, show at the Saenger Theatre, began July 2 at the Sands Bethlehem Event Center in Bethlehem, Pennsylvania. It runs through Oct. 4, ending with a concert at the Greek Theatre in Los Angeles.

Reviews report that CSN performs for three hours. Not bad for three guys who’re all around 70 and lived the rock ’n’ roll lifestyle.

“We’re playing for a long time,” Nash told South Carolina’s Charleston City Paper in June. “It’s not like we’re doing 15 hits and then getting out of there. It’s like 24 songs, because we do have a lot to choose from.”

Reviews and the Nash interview also report that many newly composed songs are in the set lists.

“Songs come at the strangest time, and you have to play them when you feel it,” Nash said.

The group also plans to make an album of new CSN songs, Nash said, and complete a project featuring nonoriginal material that it abandoned in 2012 following disagreements between Crosby and producer Rick Rubin.

CSN’s 2014 touring dovetails with the July 8 release of “CSNY 1974,” a CD box set featuring 40 previously unreleased recordings from Crosby, Stills, Nash, & Young’s 1974 stadium tour. Music from the tour, which consisted of 31 concerts performed in 24 cities, is available in multiple configurations, including a single 16-track CD and a box of vinyl LPs.

“This project has been the most difficult yet rewarding work I’ve ever done in my 50 years of recording,” Nash said of “CSNY 1974.” “It rekindled the love I have for my partners and the music we have made together.”