NEW YORK — The philanthropist Susan Newhouse, wife of billionaire publishing magnate Donald Newhouse, died Thursday at her home in New York City following a long illness.

She was 80 and had primary progressive aphasia, a disease that disables the part of the brain that processes speech and language, her husband said.

During her life, Newhouse poured money and time into colleges, libraries, theaters and other charitable endeavors. She served as a trustee or board member at Wellesley College; the New York Public Library; the Lincoln Center Theater; the Collegiate School; her Manhattan synagogue, Temple Emanu-el; and the Paper Bag Players, a children’s theater group.

Two programs that helped children were closest to her heart, her family said.

In 1976, she helped ballet dancer Jacques d-Amboise found the National Dance Institute, which today offers free programs annually to thousands of public school children. Newhouse was involved with the organization for three decades.

She was also a longtime chairwoman of The Fresh Air Fund, a nonprofit group that has been sending poor city kids on summer vacations with families in the country since the late 19th century.

“We loved the program. We loved the kids. And we eventually took a child ourselves for two weeks in the summer,” Donald Newhouse said, adding that the girl remains close to the family to this day.

Born Susan Marley in 1935, Newhouse grew up in Syracuse, where she excelled academically at a young age. She enrolled at Wellesley at 16 and graduated in 1955 at 19, her family said. She married Donald Newhouse in Syracuse shortly after graduation. He said he proposed on their second date.

In recent years, Newhouse had been dealing with what her husband called “the horror” of primary progressive aphasia. He pledged to work with a research funding organization, The Association for Frontotemporal Degeneration, to find a cure.

In addition to her husband, she is survived by sister Nanci Bronsteen; her children, Steven Newhouse, Michael New- house and Katherine New- house Mele; and six grandchildren.

Donald Newhouse, along with his brother Samuel New- house, owns Advance Publications, which owns dozens of U.S. newspapers, a cable TV company and Conde Nast, publisher of magazines including Vogue and Vanity Fair. He was the chairman of the board of The Associated Press from 1997 to 2002.

The family plans to hold a private funeral Monday and a memorial service in October.