Soledad Mexia was born in La Noria, Sinaloa, Mexico, on 13 August 1899, to Benigno and Refugio Bonillas. She was the youngest of two daughters.
At the age of 20, she married Juan Mexia, a carpenter who constructed sets for the theatre and opera in Mazatlan. The newlyweds lived for a time in Los Angeles and Phoenix but always returned to Sinaloa. The couple had seven children.
Mexia moved to south San Diego County for good in the early 1960s, living with her children until she moved to a Nursing home in 2011.
At the time of death, she had 24 grandchildren, 45 great-grandchildren, and two great-great-grandchildren.
On 30 August 2013, Mexia died due to respiratory insufficiency, 17 days after her 114th birthday, at a hospice in Chula Vista, California.