The guitarist and songwriter "passed away peacefully in his favourite chair" on Sunday at his home in Gardnerville, Nevada, according to a post on his official Instagram page.
The post, which was flooded with tributes from friends and fans, said the rocker died after "cooking an amazing dinner with his beloved wife Winifred", and described his death as a "storybook ending, on his own terms".
"He leaves a lasting imprint on the soundtrack of our lives and the hearts he has lifted. His legacy will be cherished forever."
Mason had revealed in 2024 that he was undergoing treatment for a "serious heart condition" before cancelling 2025 tour dates due to health problems.
US songwriter Stephen Bishop paid tribute to Mason on Instagram: "We did a show together back in the early 70s, and I remember how incredibly talented he was.
"I was always a fan of his early work with Traffic. I especially love his song Only You Know And I Know. We stayed in touch through the years, and he was always kind to me and an incredible guitar player."
Mason rose to fame after co-founding Traffic in 1967, alongside frontman Steve Winwood, drummer Jim Capaldi and flute-turned-saxophone player Chris Wood.
The England-born star appeared on the band's first two albums - Mr Fantasy (1967) and Traffic (1968) - and has been credited for writing some of their greatest hits such as Hole In My Shoe.
He also wrote the band's hit Feelin' Alright?, rerecorded by stars including Joe Cocker and The Jackson Five.
Traffic were inducted into the Rock & Roll Hall of Fame in 2004.
Mason left Traffic in 1968 and released his debut solo album Alone Together in 1970, which contained some of his most highly regarded songs such as Sad And Deep As You and Look At You, Look At Me.
Mason also worked as a session musician, collaborating with the Rolling Stones on their song Street Fighting Man, and teaming up with rocker Jimi Hendrix for his cover of Bob Dylan's hit All Along The Watchtower.
During a six-decade career, Mason worked with acclaimed musicians including Paul McCartney, Michael Jackson, Graham Nash and David Crosby.
He also briefly joined Fleetwood Mac for a stint in the 1990s for their 16th studio album, Time, and toured with them from 1994 to 1995.
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