A press release issued by the Opry says Howard "passed away peacefully" in Gallatin, Tennessee.
Howard officially joined the Opry in 1971, and was the oldest living member of the country music institution. In a statement, Opry Vice President and Executive Producer Dan Rogers called Howard "A force of nature in country music, at the Opry, and in life."
"We were all so lucky so many nights to hear her voice on stage and to catch up with her backstage. We’re all better for having had her in our lives.”
The Tennessean reports the news broke while the latest Opry show — featuring Vince Gill, Amy Grant and their daughters — was being broadcast live.
On stage at the Grand Ole Opry House, Gill said that he and Howard "spent an awful lot of time over on that side of the stage, telling jokes and having a great friendship for over 30 years."
Howard's music career began in the late '50s, singing demo recordings for songs written by her then-husband, songwriting great Harlan Howard. That included the original demo for Patsy Cline's "I Fall To Pieces."
In 1960, she had a hit of her own: "The One You Slip Around With." Her biggest solo success came with 1966's "Evil On Your Mind," and the follow-up "Bad Seed." She'd reach the top of the charts through her collaborations with Bill Anderson in the late '60s and early '70s, including "For Loving You," a No. 1 hit in 1967.
Howard was also an accomplished songwriter, penning hits for Kitty Wells and Connie Smith. But her most powerful composition was also a highly personal one: 1968's “My Son," which was written for her own son, killed in action in Vietnam that same year.
Howard's work with the armed forces and veteran organizations earned her several honors, including the Tennessee Adjutant General’s Distinguished Patriot Medal, and the Medal of Merit from the Commander in Chief of the Veterans of Foreign Wars.