The California Death Index, which seems to be much more reliable than social security, shows:
Margaret E. YINGLING b. 03/07/1901, mother's maiden name Gutterso* (if name is too long on index, it gets cut off), female, b. California, DIED LOS ANGELES COUNTY (70) on November 27, 1964, ss#558-34-3173, age 64
Perhaps the info you have is from the ss index that indicates her last known residential address was in Trinity County (as reported to ssdi).
I would suggest that you order her death cert from Los Angeles County at www.vitalrec.com