Lost something in Diamond Bar? Report it and get help recovering it.
One report, and we reach out to the Walnut/Diamond Bar Sheriff's Station, Diamond Bar City Hall, local transit services, and active community channels. Your report stays active, continuously matching against new found items and local posts so you don't have to search manually every day.
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
California : found property must be held by law enforcement for at least 90 days before it can pass to the finder, be auctioned or disposed of. (California Civil Code §2080.2)
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 Diamond Bar
You describe your loss
Tell us what you lost, where, and when. We gather the details that matter for recovery.
We route it to the right places
Your report goes to the Walnut/Diamond Bar Sheriff's Station, city services, Foothill Transit if applicable, and gets shared with local lost and found networks. You don't have to call around.
Your report keeps searching for you
Throughout your entire search period, your report stays active and compares incoming found items and community posts against your description. The moment a credible match appears, you'll get an alert.
Where to Report a Lost Item in Diamond Bar
Each of these agencies and services keeps lost and found records. ReportLost connects you to them all at once.
Walnut/Diamond Bar Sheriff's Station
The local law enforcement office for lost item reports and theft documentation. They maintain lost and found records for items turned in by residents. We file your report with the right precinct and provide the details they'll need. Available 24/7.
Diamond Bar City Hall
City services coordinate with local lost and found efforts and can direct you to relevant departments. We notify city staff so your loss is on their radar. Monday through Thursday, 7:30 a.m. to 5:30 p.m.; Friday, 7:30 a.m. to 4:30 p.m.
Foothill Transit Lost & Found
If you lost an item on a Foothill Transit bus in Diamond Bar, the lost and found department tracks all turned-in belongings. We identify which route your loss occurred on and submit the details. Call their Lost & Found line or let us handle the routing.
Lost Pets
If you've lost a pet in Diamond Bar, Animal Control and the Inland Valley Humane Society maintain lost pet databases and can help with recovery. We make sure your pet is registered across all local shelter systems. file a priority lost pet report
Ontario International Airport
If you left something at Ontario Airport (about 15 minutes from Diamond Bar), their Lost and Found office handles items left in terminals and security areas. We can report to their department if your loss occurred there.
⚠️ Spotted incorrect or outdated information? Let us know so we can review it.
Report Your Loss Today
The sooner your loss is logged and shared with local agencies and community networks, the better your chances of recovery. Once your report is filed, the ongoing search happens automatically for months. You've done your part; let the system work for you.
Report my lost item →Losing something in Diamond Bar means navigating several separate channels: the Sheriff's Station, the city, Foothill Transit if you were on a bus, local animal shelter systems, and various community Facebook groups. Each has its own hours, phone lines, and procedures. By the time you contact them all, days have passed.
ReportLost bridges that gap. You file once, we notify the right agencies and community networks, and your report stays live and searching for months. Instead of refreshing lost and found pages and groups yourself, your description automatically matches against new posts and found items as they come in. Once reported, you can focus on your day while the system works in the background.
Common Loss Hotspots in Diamond Bar
Items are frequently lost in and around these areas. If your loss occurred nearby, knowing the location helps us route your report to the right local department.
Downtown Diamond Bar / Copley Drive area
The city center around City Hall and local shops is a frequent loss zone. Reports here often go to city services and nearby retail lost and found departments.
Foothill Transit bus routes and stations
Items left on buses or at transit stops account for many reports. We flag these with Foothill Transit's Lost & Found line immediately.
Diamond Bar High School and nearby parks
Community gathering spots where wallets, phones, and personal items frequently turn up. Local residents often post finds in community groups.
Shopping centers and retail corridors
Strip malls and stores throughout Diamond Bar handle many lost and found items. We identify the relevant business and direct you appropriately.
Residential neighborhoods and sidewalks
Items lost during daily routines often resurface through neighbor networks and local community pages. Your report reaches these groups too.
Local Community Networks
Diamond Bar residents share lost and found posts across several platforms. Once you report with ReportLost, we connect you to these active channels.
Facebook group with thousands of members posting pet losses and finds across the region
Hyperlocal Facebook group focused on Diamond Bar pet losses
Neighborhood app where Diamond Bar residents post and discuss found items
Lost and found pet database covering the Diamond Bar area with active community alerts
Frequently Asked Questions
How long does the Sheriff's Station keep lost items?
The Walnut/Diamond Bar Sheriff's Station typically holds lost property for a period determined by state law, usually 90 days or more depending on the type of item. Check with them directly at (626) 913-1715 or (909) 595-2264 for specifics on your item. Your ReportLost report stays active much longer, so you have an ongoing alert if your item resurfaces later.
What if I lost something on a Foothill Transit bus?
Call Foothill Transit's Lost & Found line at 1-800-RIDE-INFO (1-800-743-3463) with details about which bus route and approximate time. Items are typically held for a set period. ReportLost will contact them on your behalf and include all relevant details.
Where should I start if I don't know where I lost my item?
Think about your movements that day: Were you on a bus? In a shop? At a specific location? Even a general area helps. Describe your item in detail (color, distinctive marks, where you last remember having it). ReportLost will notify all likely locations in Diamond Bar, and your report will stay active while we wait for matches.
Do I need to file a police report for a lost item?
A police report is typically only necessary if you suspect theft rather than loss. For lost items, you can file directly with the Sheriff's Station or use ReportLost, which notifies them and other relevant agencies. The Sheriff's Station can advise if a report is needed based on the circumstances.
How does ReportLost's 6 to 12 month search work?
Once you file a report, your item description stays in the system and automatically checks against new found items posted to community platforms, local networks, and agency databases. You don't have to refresh pages daily; if a credible match appears, you'll get an alert. This continuous matching is what sets ReportLost apart from a one-time police report.
Is ReportLost official or does it replace calling the police?
ReportLost is an independent service, not affiliated with law enforcement or the city. We don't replace a police report; we supplement and accelerate the process. We notify the Sheriff's Station, city services, and community networks on your behalf, and keep your search active longer than most people would manually. For emergencies, always call 911.
Lost & found in nearby cities
Start Your Report Now
Every moment counts, and every detail matters. The faster your loss is reported and shared across local agencies and community networks, the faster someone who found your item might see it. And once it's filed, your report continues searching for you for months.
Start my report →ReportLost.org is an independent service and is not affiliated with the Walnut/Diamond Bar Sheriff's Station, City of Diamond Bar, Foothill Transit, Animal Control, Ontario International Airport, or any other entity mentioned. We connect your report to these agencies and communities; we do not operate or control their lost and found systems. Always verify current contact information and hours directly with each service.