Ontario is a city of about 175,000 people in the 2020 Census with no courthouse of its own. Its cases are spread across three other cities, and the building closest to Ontario is the one that takes the fewest of them. For a paralegal filing from Ontario, the first step is matching the case type to the right district.
We handle Ontario Service Requests from Sacramento, about 383 miles away in a straight line, and the papers are served at the Ontario address by the process server we assign. Valpro Attorney Services doesn't have an Inland Empire office. You send the documents online, and the proof of service comes back once the papers are delivered.
Why isn't the closest courthouse the right one?
Haven Avenue in Rancho Cucamonga is about 4.8 miles from Ontario's Census center point. It houses three units: the criminal Rancho Cucamonga District, its Civil Division and the Appeals and Appellate Division. Ontario is on the criminal list. It's also on the list for CEQA cases from the court's Western Region, which go to that Civil Division. For ordinary civil lawsuits, though, the Where Can I File page sends Ontario to the San Bernardino Justice Center, roughly four times as far.
So a criminal subpoena for an Ontario witness can come from Haven Avenue, while a contract suit against an Ontario business is filed in downtown San Bernardino. Read the case number and the court address on the papers you send us, and confirm the district on the court's page before you file anything new.
Ontario case types and where they're filed
Straight-line distances run from Ontario's Census center point to each courthouse's Census Geocoder point.
| Ontario case type | Courthouse | Straight line |
|---|---|---|
| Small claims | Fontana District, 17780 Arrow Boulevard, Fontana | 11.6 mi |
| Limited landlord-tenant ($35,000 or less) | Fontana District | 11.6 mi |
| Probate, guardianships, conservatorships | Fontana District | 11.6 mi |
| Civil harassment and workplace violence petitions | Fontana District | 11.6 mi |
| Civil, limited and unlimited | Civil Division, San Bernardino Justice Center, 247 West 3rd Street | 18.7 mi |
| Unlimited landlord-tenant | Civil Division, San Bernardino Justice Center | 18.7 mi |
| Name change petitions | Civil Division, San Bernardino Justice Center | 18.7 mi |
| Family law and domestic violence orders | Family Law Division, Historic Courthouse, 351 North Arrowhead Avenue | 18.6 mi |
| Felonies and misdemeanors | Rancho Cucamonga District, 8303 Haven Avenue | 4.8 mi |
Two labels on the court's lists are worth knowing. Guasti is listed separately from Ontario, with the same assignments. On the restraining order list, the court also writes "Ontario (Montclair)" and "Chino (Montclair/Ontario)", which reflects how mailing names overlap at the city edges. Clerk's offices at every one of these buildings are open 8:00 a.m. to 4:00 p.m. on weekdays, per the court's page.
Serving papers at an Ontario workplace
Many Ontario Service Requests name someone at work, not at home. The rules don't change: personal delivery to the person, or substituted service at their usual place of business by leaving the papers with the person apparently in charge and then mailing a copy (CCP § 415.20(b)). What changes is the planning.
If the person works at a warehouse, distribution center, hotel or office park, put these in the Letter of Instruction:
- The building or dock number and the company name on the door, not only the street address. One street address can cover several buildings.
- Shift times. Day, swing and night shifts change who is on site and when the person can be reached.
- The front office or guard station. Say whether visitors check in at a gate, and whether the person comes out to a lobby or parking area.
- The person's role or department, so a receptionist can locate them.
- The home address too, if you have it. When a workplace attempt fails because of site security, an evening attempt at home is often next.
Workplace service has limits. A server doesn't enter areas the public can't, and the person isn't required to come out. If the employer won't let the person be reached, the attempt record shows what happened, and you can choose the next step. This is general information, not legal advice.
For a business that is itself the defendant, the address on bizfile Online matters more than the warehouse address. See the section on companies below.
Papers to serve in Ontario?
Small claims and evictions for Ontario
Ontario small claims are filed and heard in Fontana. The San Bernardino court's small claims page lists the ways to serve: an adult who isn't a party, a registered process server, the sheriff, or certified mail sent by the clerk for $15, which only works if the defendant signs the return card. The page sets a deadline of 15 days before trial for personal service on a defendant living in the county and 20 days for one living outside it, and asks that proofs of service be filed 5 days before the hearing.
Ontario evictions split by amount. Limited cases go to Fontana, which offers appointments for landlord-tenant filings, and unlimited cases go to the Justice Center in San Bernardino. The court's landlord-tenant page gives the tenant 10 days after service to respond in writing. Because that clock runs from service, Rush is worth considering for an Ontario eviction. From January 1, 2027, AB 747 also changes how an eviction summons can be posted, and our AB 747 guide has the detail.
Restraining orders for Ontario residents
Civil harassment, workplace violence, gun violence and postsecondary school protective order petitions from Ontario are handled at the Fontana District under the court's area list. An employer seeking a workplace violence order for an Ontario site files there. Domestic violence restraining orders are a family law matter and go to the Historic Courthouse in San Bernardino.
Restraining order papers usually have to be personally served before the hearing. Send us the filed petition, the temporary order if one was issued, the hearing notice and the blank response form, and tell us about any safety concerns at the address.
Filing Ontario civil cases
Attorneys in San Bernardino civil cases have had to e-file since September 2, 2025, including judgments. Self-represented parties can still file at the counter, and small claims eFiling is voluntary for everyone. Proof of service of a civil summons is usually form POS-010, and family law service is proved on FL-115.
If you'd rather not send a runner to San Bernardino, our San Bernardino County court filing page explains how we file and then serve on the same request. Our post on court messenger service for attorneys covers filing runs more generally.
Saving the drive to Third Street
An Ontario civil case is heard about 18.7 miles away at the San Bernardino Justice Center, so remote options matter. The court's technology page lists Zoom audio and video in Justice Center departments S17, S24 through S29, S33 and S35 through S37, CourtCall audio and video in a longer list of rooms, and a Microsoft Teams room in S29 only. Each courtroom decides for itself, and the court wants notice before the hearing day. For a hearing set at least 3 court days out with no testimony, the remote party tells everyone at least 2 court days ahead and files form RA-010.
The file itself can often be read from Ontario too. The court sells remote access to publicly viewable civil documents at $0.50 a page, and warns that data for cases filed before 1998 may be thin. For an older file, the court says to contact the district that holds it, which for Ontario civil cases is the Justice Center. Our document retrieval service can make that request at the counter.
Serving a company with an Ontario address
Corporations and LLCs are served through the agent for service of process named with the California Secretary of State (Corporations Code §§ 1502 and 17701.13). For a business with an Ontario warehouse or office, the agent may be a commercial registered agent elsewhere in California. Search the entity on bizfile Online and send the agent's name and address with your papers. If the agent is CSC Lawyers Incorporating Service, our page on that agent explains how service there works. Our serving corporations page covers officers and entities with no agent on file.
Ontario ZIP Codes and neighboring counties
The Census Bureau assigns Ontario three ZIP Code areas: 91761, 91762 and 91764. Ontario's close neighbors fall in two counties:
- Same county: Chino, Montclair, Upland and Rancho Cucamonga, all within 6.4 miles. Chino, Montclair and Upland use Haven Avenue for civil cases, unlike Ontario.
- Riverside County: Eastvale, 5.3 miles away, and Jurupa Valley. Their cases belong to the Riverside Superior Court, and service there counts as outside the county for small claims deadlines.
When an address isn't current, ask about skip tracing, and get each update by email. Start a new one on the Service Request form. The rest of the county is on our San Bernardino County page.