Lost something in Mountainside? Here is who holds found property.
One report and we route it to the Mountainside Police Department, the relevant local offices, and active community channels. Your report stays active, keeping the hunt alive.
What did you lose?
If there isn’t an adequate suggestion, select “Other – My item isn’t listed” and enter the item’s category. You can provide details later.
Publishing your report is free and your details stay private. The assisted search is a separate paid service, described in the Terms.
Recent activity
Across the United States
- Wrislet clutch gray/silver bag with documents · Chicago, IL, October 8
- Ring TM on top · Greensboro, NC, October 8
- Keys · Sarasota, FL, October 8
- Keys · Brookline, MA, October 7
- Camera · Monterey, CA, October 7
Local contact details reviewed on October 7, 2026.
How ReportLost works in Mountainside
You report the loss
Tell us what you lost, where, and when. We gather the details that matter: a description, the exact location in Mountainside, and how to reach you. No back-and-forth, no confusion.
We route it to the right places
We contact the Mountainside Police Department, Borough Hall, NJ Transit if applicable, and post your report to active local community channels. You don't have to call, email, or figure out who handles what.
Your report keeps searching for you
While you go about your day, your report stays active and continues to match against new found item posts, local announcements, and community alerts. You get an alert the moment a credible match appears. No daily checking required.
Where items are reported and recovered in Mountainside
These are the official channels we contact on your behalf. You can reach them directly if you prefer, but ReportLost saves you the calls and coordination.
Mountainside Police Department
The first place to report any lost item in Mountainside is the Police Department. They maintain a lost and found for items turned in by residents and businesses. We tell you which precinct covers your loss location and generate the exact information to include in your report.
Borough Hall
Mountainside Borough Hall coordinates services across the town and can assist with general lost item inquiries. They may have items turned in at municipal offices or can point you toward the right department. We ensure your report reaches the right desk.
NJ Transit Lost & Found
Lost something on a bus or other NJ Transit vehicle? NJ Transit maintains a dedicated lost and found with an online system and customer service offices. We guide you to the right NJ Transit reporting channel and ensure your item is logged.
Newark Airport (EWR)
If you lost an item traveling through Newark Liberty International Airport, EWR's Lost and Found office can help recover it. They accept reports online and by phone, and items are held for a set period. We point you to their submission form.
Lost Pets
A missing cat or dog requires immediate action. Contact the Union County Animal Shelter to report your pet and check if one matching your description has been brought in. Local community groups like Union County Lost Pets on Facebook are also vital for spreading the word fast. We help you file a priority report and tap into these networks immediately, or file a priority lost pet report directly with ReportLost for pet-specific coordination.
Union County Animal Shelter|Union County Lost Pets (Facebook)
⚠️ Spotted incorrect or outdated information? Let us know so we can review it.
The sooner you report, the sooner we start searching
Every hour counts when something goes missing. The moment you file your report, we're already reaching out to the police, borough offices, and community networks. Then we keep searching for you across all local channels for the duration of your search period. You can breathe easy knowing the work is happening in the background.
Report my lost item →Losing something in Mountainside is stressful. Whether it's your wallet, keys, a cherished ring, or your beloved dog, the usual channels work in silos: the police take a report, the borough has its own office, NJ Transit handles transit items, and community members post finds on scattered Facebook groups and Nextdoor. By the time you've called everyone and checked every page, hours have passed and momentum is lost.
ReportLost simplifies the entire process. File one report, and we immediately notify the Mountainside Police Department, Borough Hall, local transit authority, and the community networks where found items actually get posted. Then your report stays active for your full search period, matching against new posts and alerts automatically, so you're not refreshing Facebook at midnight hoping someone found your ring. We handle the legwork while you focus on what matters.
Common places where items go missing in Mountainside
These are hotspots where losses happen most often. The sooner you report, the more likely a business or neighbor has already turned your item in.
Route 22 East
The main commercial corridor through Mountainside, home to shops, restaurants, and services. Wallets, phones, and purses are frequently lost in parking areas and storefronts here.
Downtown Mountainside
The central business and community hub where residents shop, dine, and conduct errands. Lost items in this zone are often turned in to nearby shops or the police station.
Residential neighborhoods
Suburbs and tree-lined streets where residents walk, jog, and let their dogs off-leash. Jewelry, keys, and pets frequently go missing in these quieter areas, sometimes found by neighbors.
Parks and green spaces
Open areas throughout Mountainside where families and pet owners gather. Rings, phones, and collars are commonly lost here and turned in by park visitors or staff.
How the Mountainside community helps find lost items
Local Facebook groups and Nextdoor posts are where found items get reported first. We post your report across these networks so you don't have to.
Active group for lost and found pets across Union County, including Mountainside
Community groups where residents post found items and help neighbors
Hyperlocal app where neighbors share lost and found items immediately
New Jersey subreddit where people post about lost items and pets
Shops and restaurants along Route 22 often hold found wallets, keys, and phones
Common questions about lost items in Mountainside
How long does the Mountainside Police Department keep lost items?
The police typically hold lost items for 30 to 90 days before disposing of them. Contact the Mountainside Police Department at 908-232-8100 to ask about a specific item. The sooner you report, the sooner they can set it aside for you.
What if I lost something on an NJ Transit bus in Mountainside?
Report it to NJ Transit's Lost and Found at njtransit.com/lostandfound or call 973-275-5555. Provide the bus route, time, and a detailed description. We ensure your item is logged in their system and cross-reference it with community posts.
How do I file a lost pet report in Mountainside?
Call the Union County Animal Shelter at 908-851-5230 immediately to report a missing cat or dog and ask if a matching pet has been brought in. Also post in the Union County Lost Pets Facebook group. We can file a priority pet report that reaches shelters and local networks all at once.
Where should I check first if I lost my wallet or keys?
Check with any business where you were immediately before the loss, then contact the Mountainside Police Department. We coordinate this for you and ensure the item is logged in their lost and found system. Most wallets and keys are turned in within hours of being found.
Can I report a loss from outside Mountainside?
Yes. If you lost something while in Mountainside but live elsewhere, you can file a report with us and we'll contact the Mountainside Police Department and local offices on your behalf. We also post across community networks so local residents can help in the search.
Is ReportLost.org an official Mountainside service?
No, ReportLost is an independent service. We're not part of the police department or borough government, but we work directly with them and local organizations on your behalf. We file your report with the right official channels and keep it active across community networks for months, so you don't have to do the follow-up yourself.
Lost & found in nearby cities
File your report now and let us handle the rest
The longer an item sits unclaimed, the greater the chance it gets misplaced or disposed of. Start your report today. Once you're done, our team immediately reaches out to the Mountainside Police Department, Borough Hall, local transit, and community groups. Your report stays active and searching for a full 12 months, so you can stop worrying and let us find your item.
Start my report →ReportLost.org is an independent service and is not affiliated with the Mountainside Police Department, Borough of Mountainside, NJ Transit, Newark Airport, Union County Animal Shelter, or any other official entity mentioned. We file reports on your behalf and coordinate with these organizations, but we do not represent them and do not replace official lost and found processes. Always follow up directly with official channels for urgent inquiries.