Forty years ago, when American Airlines Flight 191 crashed just beyond O’Hare Airport’s boundaries, the jetliner struck earth — not the trailer park next door, nor the oil tanks nearby, nor any of the many commercial buildings in the area.

What the DC-10 hit on May 25, 1979, was a field north of Touhy Avenue and east of Elmhurst Road.

To this day, the land remains an open field. Even as the airport and surrounding suburbs have grown, the property where 273 people died has remained as it was.

But that could change in the next few years, with plans for a highway to cut through the roughly 40 acres that now serves as a natural memorial, marshy and peaceful, the dandelions and shrubs looking as they might have looked on that awful day 40 years ago Saturday.

Why wasn’t the land ever developed? And why did the site never get even a memorial plaque or statue? The crash was, after all, the deadliest U.S. aviation disaster until the 9/11 terror attacks.

Consider it a case of very long-term planning. Just because the site was untouched doesn’t mean it was forgotten.

The property is owned by the city of Chicago, even though Cook County property maps show it as unincorporated land tucked between the airport and neighboring Des Plaines and Elk Grove Village.

There’s a telltale sign of ownership: a small Chicago Police Department building that fronts the property on Touhy. The K-9 Training Facility is where officers train police dogs for the narcotics and patrol divisions.

Chicago appears to have owned the property for decades.

It’s gained strategic value from its proximity to Interstate 90, now known as the Jane Addams Memorial Tollway.

For decades, city and suburban officials and executives of the Illinois State Toll Highway Authority have haggled over creating a western access for O’Hare. It would involve a tollway to be designated Interstate 490 to connect the Jane Addams with the Tri-State Tollway along the western flank of the airport.

To accomplish that, the easiest link would be right through the crash site.

“The land was always seen as an essential part of the ring road,” said Greg Bedalov, former executive director of the toll authority and current chief executive of the Illinois Sports Facilities Authority. “I don’t recall its history ever being discussed.”

The highway construction is still in its early stages. Ronald Lunt, a founder of the real estate firm Hamilton Partners who is part of an advisory committee on western O’Hare access, said construction at the crash site might be done by 2023. He said the authority hopes the entire highway loop will be built by 2025.

“That site was never regarded as development land,” Lunt said. “It was always my impression that the area was best used for [water] detention.”

He said he remembers watching the fireball from the crash of Flight 191 from an office building about a mile away.

“I don’t know if the tollway would ever plan on some kind of public marker once the highway is built,” Lunt said. “It’s getting to the point where many people just don’t remember this any more.”

Construction plans cleared a bureaucratic hurdle in January 2017, when the Chicago City Council authorized the sale to the tollway agency of 530 acres around O’Hare. The $96 million sale included the crash site.

“Our engineering and planning teams are aware of the location of the Flight 191 crash site,” tollway spokesman Dan Rozek said. “While final design plans on the I-490 Tollway project are not complete, we do anticipate the roadway will cross that site.

“The tollway has reached a tentative agreement with Chicago for transferring the land needed to construct I-490 but has not yet finalized that transaction. We’d also note that a formal memorial already exists in nearby Des Plaines.”

The Des Plaines memorial, in a park nearby, might have to suffice. Visit the field itself, and you might notice a couple of markers among the trees. They show where workers have taken soil samples for the tollway project.