Why Are Stray Cats and Rats Disappearing From America’s Largest Landfill?

For over 50 years, rats and stray cats ruled Puente Hills Landfill in Los Angeles County. At its peak, it was the second-largest landfill in the entire country.

Then, on 31 October 2013, the lorries stopped coming — and slowly, the animals that had called this place home for decades began to disappear.

So what actually happened? The answer isn’t pest control. It’s something far bigger.

Puente Hills Landfill: A Brief History

Puente Hills wasn’t just big. It was massive — 1,365 acres of rubbish, piled up over 56 years of daily operation, making it one of the largest landfills the United States has ever seen.

For generations of rats, feral cats, birds, and other scavengers, it wasn’t a tip. It was home turf, offering an endless, reliable source of food in the middle of a busy urban region.

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That changed the moment the landfill closed for good in October 2013.

Why the Animals Are Leaving Puente Hills Landfill

The simplest explanation is also a real one: the food disappeared. For decades, this mountain of rubbish was an all-you-can-eat buffet for anything that could scavenge. Once the deliveries stopped, so did the incentive to stay.

But that’s only part of the picture. Los Angeles County is turning the former landfill into Puente Hills Regional Park — its first new regional park in 30 years — and that transformation is reshaping the entire local ecosystem, not just removing a food source.

Restoring the Native Landscape Beneath the Rubbish

As part of the park project, crews are restoring native coastal sage scrub, oak woodland, and chaparral: the exact landscape that stood on this site before the landfill was ever built. The Wildlife Conservation Board has committed millions of dollars in restoration grants to bring this habitat back to life.

Wildlife Returning to Puente Hills Landfill Park

As native plants return, so do native animals. Coyotes, bobcats, deer, and red-tailed hawks are all part of the ecosystem this land supported long before it became a dumping ground, and they’re moving back in as the habitat recovers.

Nearby, a purpose-built wildlife underpass now allows bobcats and coyotes to cross a busy road safely, reconnecting the site to the wider Puente-Chino Hills wildlife corridor. Rangers have confirmed both species are already using it.

For the rats and stray cats that once thrived here, this means competing with — or simply being pushed out by — the animals that occupied this land first. It isn’t just a loss of food. It’s a loss of territory.

From Landfill to Regional Park: What Happens Next

Where a mountain of rubbish once stood, visitors will soon walk trails, sit beneath oak trees, and watch hawks circle overhead. Puente Hills Regional Park is set to become LA County’s first new regional park in three decades, built directly on top of its industrial past.

The disappearance of the site’s rats and stray cats isn’t a mystery with a single cause. It’s the result of a landfill closing, a habitat being restored, and an ecosystem slowly returning to what it looked like before the rubbish arrived.

Would you visit Puente Hills Regional Park once it’s built on top of a former landfill? Let us know in the comments.

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