Butcher dominated the 1,100-mile sled dog race in the late 1980s.
In 1986, she became the second woman to win the grueling race from Anchorage to Nome. She added victories in 1987, 1988 and 1990 and finished in the top four through 1993.
In 1979, Butcher helped drive the first sled-dog team to the 20,320-foot summit of Mount McKinley, the highest peak in North America.
Butcher ran her last Iditarod in 1994 when she decided to have children. She has two daughters, Tekla and Chisana, with her husband, attorney and musher David Monson.
Three years ago, when she was considering a comeback, doctors found Butcher had polycythemia vera, a rare disease that causes the bone marrow to produce excess blood.