The Hollywood veteran died surrounded by family and friends, her manager said in a statement late Thursday.
Henderson, who played effervescent mom Carol Brady on the hit TV series, was most recently seen in the audience at the finale of Dancing With the Stars on Monday, November 21.
"She looked great," a source tells Us Weekly. "She was with a female friend or relative and was in the front row to the left of the judges."
The actress, singer and talk show host, who was a contestant on the ABC dancing competition in 2010, "enjoyed the show so much," the source adds. "Even the audience warm-up guy pointed her out as 'America's favorite mom' and everyone cheered for her. She was such a wonderfully nice lady."
The Indiana native started her career onstage and made her Broadway debut in Wish You Were Here in 1952. Ten years later she became the first woman to guest host The Tonight Show With Johnny Carson and later had a role on the Today show, doing weather and news.
Her best-known role came in 1969, when she made her debut on ABC's The Brady Bunch, as the mother of three daughters who married a man with three sons. The series ran for five years till 1974.
Henderson, who was married twice and had four children, went on to host a cooking show, cohosted NBC's Later Today and hosted her own talk show on Retirement Living TV.