Reagan will lay in repose Wednesday and Thursday before being buried Friday at the Reagan Library in Simi Valley, California, next to her husband, Ronald Reagan.
The public will be allowed to visit Wednesday from 4 to 10 p.m. ET and Thursday from 1 to 5 p.m. ET, the Reagan Library announced on Facebook
First lady Michelle Obama will be attending the funeral, a White House official said Monday. On Tuesday, Hillary Clinton's campaign spokesman tweeted that she would also attend the services.
".@HillaryClinton is going to drop off the trail briefly on Friday to attend Nancy Reagan's funeral services in California," Nick Merrill tweeted.
Reagan died Sunday in her home in Los Angeles of congestive heart failure at age 94.
Revered in Republican politics, Reagan was known as a fierce protector of her husband, both personally and politically. She also launched the "Just say no" anti-drugs campaign and advocated for stem-cell research later in life.
After she and her husband left Washington, she became his protector again as he struggled with Alzheimer's disease until his death in 2004. Afterward, she remained a staunch guardian of his image and legacy.
When then-President Reagan was shot in March 1981, only she and a few others knew how badly hurt he really was. And after the assassination attempt, the President's safety was Nancy Reagan's No. 1 preoccupation.
She'd also had her own medical challenges. She was diagnosed with breast cancer in 1987 and underwent a mastectomy.
But she maintained an upbeat view -- even when it didn't involve gazing adoringly at her husband, as she famously did in countless pictures.
In a 2001 interview which took place on Ronald Reagan's 90th birthday, CNN's Larry King asked the former first lady whether she felt that fate had treated her badly.
"No, no. When you balance it all out, I've had a pretty fabulous life," she said.
Nancy Reagan is survived by Patti Davis and Ron Reagan -- her two children with Ronald Reagan -- and Michael Reagan, a son from Ronald Reagan's first marriage to Jane Wyman. Maureen Reagan, Ronald Reagan's daughter with Jane Wyman, died in 2001.