Looking for the area code for Oshkosh, Wisconsin? Oshkosh is served by area code 920, now joined by the newer 274 overlay covering the same region. This guide breaks down exactly which codes cover Oshkosh and its neighborhoods, how to dial locally and internationally, the ZIP codes involved, and how to protect yourself from scam calls.
Oshkosh Area Codes: Fast Facts
| Detail | Information |
|---|---|
| Primary Area Code | 920 |
| Overlay Area Code | 274 |
| Time Zone | Central Time (CT) |
| Major County | Winnebago County |
| Region | Northeast Wisconsin / Fox Valley |
| Country Code | +1 (USA) |
Area Code Breakdown & District Mapping
Oshkosh sits on the western shore of Lake Winnebago at the southern end of the Fox Valley, known worldwide for the annual EAA AirVenture fly-in. Its numbers come from an overlay pair that shares the same geography:
- Area code 920 — serves northeastern Wisconsin and the Fox Valley, covering Oshkosh and Winnebago County. This includes Downtown along the Fox River, the UW–Oshkosh campus area, and neighboring communities such as Neenah, Menasha, Fond du Lac, and Omro.
- Area code 274 — an overlay introduced for the 920 region to add new numbers. It covers the exact same area, so a 274 number can belong to anyone in Oshkosh and the wider Fox Valley.
Area code 920 has served northeastern Wisconsin since 1997. As demand grew across the Fox Valley, the 274 overlay was added over the same territory rather than splitting the region, so existing customers kept their numbers. Because 274 overlays 920, both codes serve identical communities.
Local Dialing Rules & International Calling
Because of the 274 overlay, the Oshkosh area requires mandatory 10-digit dialing on every call. Always include the area code, even for local calls.
- Local / domestic: dial 920-XXX-XXXX (or 274-XXX-XXXX).
- 11-digit: you can also dial 1-920-XXX-XXXX; the leading 1 is the country code for the US.
- International: dial your country’s exit code, then +1 920 XXX XXXX — for example, 00 1 920 XXX XXXX from the UK or Europe, or +1 920 XXX XXXX from any mobile phone.
Major ZIP Codes Covered
Oshkosh’s numbers align with ZIP codes including 54901 (north and central Oshkosh), 54902 (south), and 54904 (west), along with surrounding Winnebago County communities.
Spam & Scam Call Warnings for Oshkosh
Scammers frequently spoof local 920 and 274 numbers so calls look like they come from a neighbor or a local business. Oshkosh residents commonly report:
| Scam type | What to watch for |
|---|---|
| Government impersonation | Fake IRS or Social Security calls demanding payment |
| Utility impersonation | Threats to shut off power or gas unless you pay immediately |
| Student & tuition scams | Calls about “unpaid tuition” targeting UW–Oshkosh students |
| Prize & sweepstakes scams | Requests for a “processing fee” to release winnings |
To stay safe: never share personal or financial details with an unexpected caller, block suspicious numbers, and verify unfamiliar callers with a reverse phone lookup before calling back. If a call feels urgent or threatening, hang up and call back on an official number. Report unwanted calls to the FTC at reportfraud.ftc.gov and register at DoNotCall.gov.
Nearby Wisconsin Cities
Explore area codes for other Fox Valley cities: Appleton and Green Bay. See more on our Wisconsin hub or browse all US city area-code guides.
Frequently Asked Questions
What is the area code for Oshkosh?
The primary area code for Oshkosh is 920, now overlaid by 274 across the same region.
What is the 274 area code in Wisconsin?
274 is an overlay area code covering the same territory as 920, including Oshkosh and the Fox Valley. It was added to supply new phone numbers as 920 filled up.
What time zone is Oshkosh in?
Oshkosh is in the Central Time Zone (CT) and observes Daylight Saving Time.
Do I have to dial the area code in Oshkosh?
Yes — because of the 920/274 overlay, 10-digit dialing is required for all calls in the Oshkosh area.
Which county is Oshkosh in?
Oshkosh is the county seat of Winnebago County, which both 920 and 274 serve.
Stay Safe & Explore More
- Verify an unknown caller in our Scam Alerts directory.
- Comparing nationwide numbers? See our Toll-Free Numbers guides.