Jeanette Nesbitt Hillyer was in her mid-20s on Memorial Day in 1947 when she heard the boom.
Her father raced from the family's Port Deposit home toward the sound and the smoke.
He was one of the first people to reach the site of the worst airliner crash in American history to that day.
Eastern Airlines Flight 605, a DC-4 aircraft, was flying from La Guardia Airport in New York City and heading for Miami when the plane suddenly fell out of the sky and crashed into the swamps outside of Port Deposit town limits.
All 53 of the plane's passengers and crew were killed.
Hillyer said her father was forever changed by that day as he walked through mangled wreckage and dismembered bodies.
"I was very young when it happened," said Hillyer, now 89 years old. "I've been thinking about that day for the last 60 years."
The crash put Cecil County into the news nationwide as newspapers covered the mysterious circumstances of the incident.
Just three miles behind Flight 605 was a plane full of Civil Aeronautics Board investigators heading home from a probe of a DC-4 crash, according to the CAB incident report. They saw Flight 605 plummet 6,000 feet through clear skies to the ground just before 6 p.m.
The investigators' plane landed at Aberdeen Proving Ground and rushed to the crash site off north Principio Road. They were met by firefighters from the Perryville, Water Witch and Havre de Grace fire companies, countless police officers and men from the Bainbridge Naval Training Center.
According to the Havre de Grace Record, Chief Walker of the Havre De Grace Police Department was one of the first to reach the scene on foot.
"I'll never forget the horror of that first glimpse I received when I entered the clearing," he said. "The tangled wreckage of the airliner was a blazing inferno and I realized that all of the passengers must surely be dead."
County historian Mike Dixon said the Historical Society of Cecil County still receives phone calls and letters inquiring about the crash.
"We have had some relatives call about it through the years, but now we would probably be heading into the second generation of the victim's relatives," he said.
For Hillyer, that awful day more than 60 years ago has always been something that stirred her deeply inside.
"I always felt so bad in my heart for those people and the people who responded," she said.
This past year, Hillyer began to do something about it and consulted the Stewart Companies, which now own the land where Flight 605 crashed. Together they devised a granite obelisk monument with the inscription, "In memory of the passengers and crew that perished near here on Eastern Airlines Flight 605, May 30, 1947."
Hillyer tried to track down relatives of the victims for a dedication ceremony to take place later this month, but she couldn't find updated contact information. Nevertheless, she said she feels a little more content now, knowing that their memory will forever be just a few feet away from a sleepy Cecil County road.
"I'm so proud of the monument and I'm glad to get this done," she said Wednesday.
To this day, the crash of Flight 605 remains one of the few airline crashes in American history with an undetermined cause.