Margaret Anne Cargill, 85; San Diego Billionaire and Philanthropist

Margaret Anne Cargill, 85, a philanthropist and an heir to Minneapolis-based grain-trading conglomerate Cargill, died Tuesday at her La Jolla home of complications from chronic obstructive pulmonary disease.

Cargill’s worth was estimated at $1.8 billion by Forbes magazine in 2005, making her the third-richest San Diegan last year.

Her favorite causes were the American Red Cross, the Nature Conservancy, the Smithsonian Institution’s National Museum of the American Indian, the Salvation Army and St. Paul’s Cathedral in San Diego.

Born Sept. 24, 1920, in Los Angeles, Cargill grew up in the Midwest and, after receiving a degree in arts education from the University of Minnesota, moved to Southern California. She divided her time among Idyllwild, Borrego Springs and La Jolla.