Jasmine Nguyen of Anaheim was mortally injured during the Fourth of July incident, which occurred Friday night in the 8000 block of Cornflower Circle, north of La Palma and Stanton avenues.
"Our hearts are heavy as we come together to support a young, single mother, Bi Doan and her family during an unimaginable time of loss," a statement on GoFundMe.com said. "The sudden and tragic passing of her 8-year-old daughter Jasmine on the 4th of July from a fireworks accident in Buena Park has left a void that words cannot fill."
8-year-old girl dies after illegal fireworks display misfires in Buena Park; homeowner arrested
More than 1,300 donations had raised nearly $66,000 as of Wednesday morning.
Photos on the fundraiser page showed Jasmine smiling and feeding a bird on her shoulder, holding an achievement award from school, visiting a pumpkin patch, and posing in a purple dress with a matching-colored bow in her hair.
"Still reeling from the sudden loss of her father just four months ago, Bi now bears the heavy responsibility of caring for her elderly mother and her only child left - a 7-year-old daughter - while struggling to hold her fractured family together," the statement said.
Officers were patrolling a Buena Park neighborhood on Friday after seeing a large quantity of fireworks detonate in the area, and observed family members "frantically carrying a child into a residence."
They stopped and attempted life-saving efforts before the girl was rushed to UC Irvine Medical Center, where she was pronounced dead.
"Through initial investigation, a large illegal fireworks display, which was placed in the street by the homeowner, failed and began misfiring toward the residence where the child was," police said Saturday. "This caused other illegal fireworks to ignite, which were near the child and others. At some point, the child had been struck, causing fatal injuries. Several other individuals were present, but no significant injuries were reported."
The department added that the homeowner was arrested, and charges are pending upon review from the Orange County District Attorney's Office. Police were working with Orange County Fire Authority investigators and the Orange County Sheriff's Department Bomb Squad.
Earl Decastro, 46, was arrested and booked for involuntary manslaughter, authorities said. He has since bailed out of jail.
Unlike some Southland cities that ban residential fireworks, Buena Park allows so-called "Safe-and-Sane'' fireworks. However, investigators say a large number of fireworks that detonated in the fatal explosion were illegal.
City News Service contributed to this report.