Toshiko d’Elia, who emerged from the destitution of postwar Japan to achieve renown in the United States as a marathon runner, taking up the sport at age 44 in the 1970s when few older women were doing so, died on Wednesday in Allendale, N.J. She was 84.

The cause was brain cancer, which was detected two months ago, her daughter, Erica Diestel, said. D’Elia, who died at her daughter’s home, lived in Ridgewood, N.J.

At 100 pounds and a little over 5 feet tall, d’Elia was a powerful runner, and a resilient one. At 49, she completed the Boston Marathon in 2 hours 58 minutes 11 seconds, shortly before she was found to have cervical cancer. Eight months later she resumed training, and eight months after that, in the world masters championship in Scotland, she ran 2:57:20, the first time a woman 50 or older had bettered three hours.

Over the years she broke many age-group records. Mary Wittenberg, the president of New York Road Runners, called her “our queen of the roads.”