She was the co-founder of I. Magnin, an upscale "specialty store" in San Francisco, California.
[1][2] In the wake of the California Gold Rush, she decided to immigrate to the West coast of the United States with her husband and children.
[2][5][6] Two years later, in 1877, she moved the business to a larger store in San Francisco, and it became known as I.
[2][3] They had eight children: Samuel, Henrietta, Joseph, Emanuel John, Victor, Lucille, Flora, and Grover.
[5] San Francisco artist May Slessinger painted miniature portraits of Mary Ann Magnin and her son Grover.