For a time, the Paranormal Activity series could be beat and one of the highlights critically and financially was the third entry.
The family’s house is located at 19155 Mayall Street in Northridge, California. At the time the movie came out, the address was not known, but I was able to find the house thanks to an individual who went to a press screening of the film at the house and remembered it was in Northridge.
Thanks to the excellent sleuthing of super-fan, Kevin Neff, grandma Lois’ house has been found. That’s the good news, but the bad news, is that it was victim to this year’s Altadena fires. It was located at 425 Las Flores Drive in Altadena, California. I took pictures from the real estate listing for comparison shots. I’ve also included Kevin’s story of his search as well. Thanks for your dedication, Kevin!
The Search for Grandma Lois’ House: A Two-Year Journey through Movie Magic and Unthinkable Tragedy. by Kevin Neff
In 2023, I began a quest that would consume far more time—and stir far more emotion—than I ever anticipated: finding the real-world filming location used as Grandma Lois’ ranch house in Paranormal Activity 3 and The Marked Ones. At first, it was simply a personal mapping challenge, inspired by my 25-year career in digital cartography. I’ve always been drawn to difficult location-based puzzles, and this one felt like the perfect opportunity to put my geographic sleuthing skills to the test.
My family and I are big fans of the Paranormal Activity series, so when I realized no one had yet identified this specific location, I took that as an open invitation. Most of the franchise’s filming spots had already been uncovered and cataloged online—but not this one. That mystery intrigued me more than anything. Why had it remained hidden?
To pierce through the layers of "movie magic," I had to ignore the onscreen implications that placed the house in Moorpark, California. Being raised as a Southern Californian, I sensed the true location was likely somewhere in the Greater Los Angeles area. Still, with no solid leads and almost no identifiable visual clues, I knew this would be a true needle-in-a-haystack scenario—only this haystack spanned 34,000 square miles.
For the next two years, I poured countless hours into Google Earth, scanning satellite images and Street View from Ojai to Santa Ana. I even expanded my search into the Napa Valley and Santa Barbara regions, hoping to catch a glimpse that would confirm the house’s identity. Each potential lead turned into another dead end.
Eventually, I tried a new approach. I reached out to several minor cast members through social media, hoping someone might recall a detail that could help. No one responded. I scoured filming venue rental websites, compared architectural details, and even attempted to reverse-image search screen grabs from the films using AI-powered tools. The exterior footage from the movies was scarce and often darkly lit, making any matches nearly impossible to confirm.
By early 2025, my search was losing momentum—until a single thought sparked a breakthrough. I began revisiting filming locations from The Marked Ones, particularly the crash scene shot at a random intersection in Altadena. Why had the production team traveled so far from central LA for that one scene? Acting on instinct, I added "Altadena" to my next round of web searches.
What happened next left me speechless.
The very next search result returned a 2018 real estate listing. The thumbnail image showed a stunning colonial-style estate—bright, elegant, and unmistakably the same house used as Grandma Lois’ ranch. The contrast between the home’s on-screen portrayal as dark and foreboding and its real-life charm was striking. After more than two years of searching, the mystery was solved.
The listing detailed the home’s history and amenities, and included a YouTube video tour showcasing its sprawling grounds and stables. Watching that video was surreal—like standing at the finish line of a marathon I never expected to complete. I replayed it a dozen times, soaking in every angle, every detail.
Then, with great excitement, I entered the address into Google Earth to view its exact coordinates. But as I typed in “Altadena,” a sense of unease crept in—like a quiet warning. When the map finally zoomed in, my heart sank. The property was gone. Not abandoned but decimated. The home and all nearby structures had been reduced to nothing but rubble and ashes.
In that moment, I recalled satellite images I’d seen just months earlier while exploring The Marked Ones filming locations. A massive wildfire had swept through the Altadena area in January 2025, leaving a trail of devastation. Now, I understood the full impact. The iconic home I had spent years searching for had been destroyed before I ever found it.
The joy of discovery was instantly replaced by a deep sadness—not for myself, but for the property owners and community who suffered such loss. The destruction visible in satellite imagery is harrowing, and the reality hits hard: this was more than a film location. It was someone’s home. A piece of history, erased.
What began as a cinematic curiosity ended in a profound reminder of real-world fragility. In moments like this, perspective matters. My thoughts and prayers are with the owner and the people of Altadena who continue to rebuild and heal.
Link to the 2018 real estate website featuring the property: