As news of her unexpected death on Wednesday circulated among Florida’s Republicans, many offered tributes to Mary Ellen Miller, a revered party elder stateswoman who twice chaired the party in Miami-Dade County.

“Mary Ellen was a pioneer in the rise of our GOP in South Florida,’’ said U.S. Rep. Ileana Ros-Lehtinen. “She helped me and so many candidates get started when even registering as a Republican was a loser’s gamble.

“Mary Ellen organized voting registration drives and changed the conservative panorama for us candidates. She was a bridge builder and saw the rise of our Grand Old Party.”

Miller, a Hialeah native, died in hospice care at her Venetian Island home. She was a dignified, private person who declined to discuss her personal life even with close friends, according to Liliana Ros, a longtime GOP committeewoman.

A niece, Trudy Miller Monaco, who helped care for her aunt in the final weeks, said Miller’s illness began last fall, but she never disclosed its nature even to caregivers, and refused hospital treatment.

Born April 20, 1928, Miller was 84.

Often compared to former British Prime Minister Margaret Thatcher, Miller advised Republican governors, local officials, members of Congress and the Florida Legislature.

She was known for being as discreet as she was connected. It’s said that she never spoke ill of anyone, even Democrats.

“Even after she retired, we still went to her,’’ Ros said. “She knew everything: state laws, party laws. She was very gentle, sweet. She had no ego, and that in politics that is very unusual. … She would get upset if you praised her.’’

Over the years, Miller supported Sen. Marco Rubio, former U.S. Rep. David Rivera, both Bush presidents, and former Gov. Jeb Bush, among others.

“Mary Ellen was a great Republican and an even finer person,’’ Jeb Bush, who’d been the county’s party chairman in the 1980s, wrote in an email. “No one worked harder. No one was more committed. You could count on Mary Ellen Miller, and everyone did.’’

Miller led the party from 1991-1996, and again from 1999-2008, during Bush’s two terms as governor.

She was a seasoned operative who’d headed a lobbying group called Women for Responsible Legislation and the Committee for a Strong Miami, a political-action committee that then-Miami Commissioner Joe Carollo established in 1985 to lobby for the “strong mayor’’ form of government.

“I tend to believe that there is a great need for accountability in our government,” Miller told a reporter at the time.

Miami attorney Jefferson Knight, former Republican National Lawyers Association Florida chairman, called Miller “one of the most shrewd judges of character, with an absolutely uncanny ability to read and understand people...She almost had ESP,’’ a “skilled diplomat’’ with flawless grammar.

“She spoke in paragraphs,’’ said Knight. “I was astonished, after knowing her for years, to learn that she never attended college.’’

Miller also worked with businessman Stanley G. Tate, a party heavy hitter, on the Elephant Forum, an influential Republican club.

She quietly wielded power in Miami-Dade and Tallahassee, Tate said, and always went to the capital for legislative sessions.