She died of congestive heart failure on Sunday at her Los Angeles home.
Representatives of presidential families stretching back to the Kennedys attended, with First Lady Michelle Obama and former first lady and ex-secretary of state Hillary Clinton joining former president George W. Bush in the front row.
Hillary Clinton praised the Reagans for starting a "national conversation" about HIV/AIDS on Friday- a comment that drew backlash from LGBT advocates online who argued the former president and first lady did not do enough soon enough to draw attention to the epidemic.
A short time later the Democratic presidential hopeful performed a climbdown on Twitter. "And if something is about to become a problem I'm not above calling a staff person and asking about it", Mrs. Reagan said in a 1987 speech.
Nancy Reagan called her husband's presidential library "the shining city on the hill", using a phrase that President Reagan had borrowed from history to describe his aspirations for the nation.
Chad Griffin, the president of the Human Rights Campaign and a former Clinton White House aide, knocked the Clinton on Friday for incorrectly holding Reagan up as an activist.
"The Reagans had a great relationship and I think there's no question that a great part of his success came from her belief in him as well as his belief in the people of America", Wilson said.
"People died while Reagan administration officials ignored pleas from government scientists and did not allocate adequate funding for Aids research until the epidemic had already spread throughout the country", wrote the journalist Randy Shilts in his book "And the Band Played On " , about the disease's rise".
Kohli's biggest plus is taking up challenges, lauds Dhoni
The veteran Yuvraj Singh kept Kohli company, with the pair's combination of caution and aggression blunting the Pakistan bowlers. It's this consistency that has seen him boast of an impressive average of 53.55 in T20Is, the best in the country.
"And she acknowledged the 1.2 million people living with HIV in the United States today, with about 50,000 people newly diagnosed each year".
First Ladies. In this January 17, 2003 file photo Rosalynn Carter, Barbara Bush, Betty Ford, Nancy Reagan and Hillary Clinton are pictured.
Heavy rain had been forecast for the ceremony, and guests were ushered into a cavernous waterproof tent behind the library.
Thanks to the tireless efforts of people like Nancy Reagan, I've never been more optimistic that we are getting closer to the day when every single patient can get the care they need and deserve.
"They truly loved each other", Edwin Meese, the longtime Reagan aide who served as attorney general in his Cabinet, told reporters.
Nancy Reagan was laid to rest next to her husband of 52 years, Ronald Reagan, on the grounds of the Reagan Library.
Early in the service, former Canadian Prime Minister Brian Mulroney recalled how the late President Ronald Reagan once joked to him privately about their respective wives, "You know, Brian, for two Irishmen, we sure married up".