Hill focused on establishing clinics in rural areas where women had no access to abortion services. She opened more clinics than anyone else in the United States, sometimes drawing 1,000 protesters at a time. She sued protesters 34 times for blocking entrances and physically preventing women from entering the facilities.
"She's probably the toughest person I ever knew," said her brother Dan Hill. "She's the only person I knew who wore a bulletproof vest to work or was supposed to wear one to work. People really wanted to kill her, and she never flinched."
In 2007, Hill received the Nancy Susan Reynolds award from North Carolina for public advocacy in the face of personal risk.
"She was a determined pioneer for women's rights, always elegant and super brilliant," said Lajuan Carpenter, Hill's assistant at the National Women's Health Foundation, which has clinics in Raleigh, as well as in Georgia, Indiana and Mississippi.
Hill, who was born Aug. 7, 1948, in Durham, N.C., and graduated from Meredith College with a social work degree in 1970, began her career in 1973 in a Florida abortion clinic outside Miami one week after the Supreme Court decision Roe v. Wade made abortion legal.
A small girl walked through Hill's door that day, hands curled by cerebral palsy, pregnant by an abusive uncle. Hill recalled in 2007 that the girl was too stricken and disabled to speak about her problem, but her mother had driven her 250 miles that morning to fix it.
Hill said it was the women's stories that kept her motivated even though bomb threats, death threats, arsonists and insults marked her career.
"If people knew the stories, they wouldn't be so vicious," Hill said.
Dan Hill said his sister always loved a good fight and never backed down. But she was also very compassionate, he said.
"The day she found out her twin sister had breast cancer, she closed up her office in New York and moved down here to take care of Nancy," Dan Hill said. Nancy Hill died of cancer in 1991.
In addition to Dan, Hill is survived by another brother, Frank.
One of Hill's doctors in Florida, David Gunn, was killed in 1993 after being shot three times in the back by a protester, Michael Frederick Griffin, now serving a life sentence. Last year, Hill appeared on the "Rachel Maddow Show" on MSNBC after Dr. George Tiller was shot dead in his church where he was serving as an usher. Tiller was one of the nation's few providers of late-term abortions.
"We're still here, and we're going to be here," she told Maddow.
"In spite of recent threats, she wouldn't wear the bulletproof vest," said her longtime friend Ann Rose. "She was not going to let them control her life. She wasn't going to be intimidated."
As for her clinics, "They will go on as always," Rose said, "except without such a prominent voice."
Friedman writes for the News & Observer of Raleigh, N.C., a McClatchy newspaper.