Michigan's 948 Area Code: Oakland County & Local Numbers

Quick answer: The 948 area code is an overlay that shares the exact same footprint as 248, covering Oakland County, Michigan — Troy, Southfield, Farmington Hills, Pontiac, Royal Oak, and dozens of suburbs just north and west of Detroit. It runs on Eastern Time and requires 10-digit dialing for every local call.

Introduction

Oakland County is one of Michigan's economic engines, and its phone numbers reflect that. The 948 area code was layered onto 248 to keep pace with a county that mixes corporate headquarters, automotive engineering campuses, and some of the state's wealthiest residential suburbs into one of the densest number markets in the Midwest.

Geographically, this is the county that runs from Pontiac's old General Motors roots through Auburn Hills' modern automotive campuses, past the retail corridors of Troy and Novi, into the leafy, high-income suburbs of Birmingham and Bloomfield Hills. It is home to Fortune 500 offices, major hospital systems, and a steady flow of new residents and businesses that have pushed the original 248 code past its limits.

This guide walks through exactly where 948 reaches, why it now shares Oakland County with 248, the cities it covers, how to dial it correctly, the business case for a local number, and how to spot the scam calls that target the region.

Where the 948 area code reaches

The 948 area code covers the same ground as 248: all of Oakland County, one of southeastern Michigan's largest and most affluent counties, sitting just north and west of Detroit. It reaches corporate corridors like Troy and Southfield, automotive engineering hubs like Auburn Hills, entertainment districts like Royal Oak, and upscale residential communities like Birmingham and Bloomfield Hills.

Because 948 is an overlay rather than a split, it does not claim its own separate slice of the map. Every one of those cities has some numbers on 248 and some on 948, assigned as carriers work through each available block. The pattern mirrors what Illinois did around Chicago's suburbs — the 947 area overlays 847 the same way 948 overlays 248, a sign that both regions grew too fast for a single code to keep serving new lines.

A short history of Michigan's 948 code

Oakland County's numbering history traces back to the old 313 code, which once covered all of Detroit and its surrounding suburbs. As the region grew through the 1990s, 313 split repeatedly: 810 broke off in 1993 to cover the suburbs outside Detroit proper, and in 1997 810 itself split again, handing Oakland County its own dedicated code — 248.

For roughly two decades, 248 comfortably served the county on its own. But Oakland County kept growing — new corporate campuses, an expanding automotive and tech sector centered around Auburn Hills, and a wave of mobile and VoIP lines that ate through the remaining number blocks far faster than landlines ever had.

To avoid forcing a wholesale renumbering of the county, Michigan regulators approved an overlay rather than another split. The 948 area code was introduced on top of 248's existing footprint, and 10-digit dialing became mandatory for every call placed within the county.

Major cities in the 948 area code

The 948/248 overlay spans Oakland County's mix of corporate, industrial, and residential communities. The largest and most notable include:

Troy anchors the retail and corporate side of the county with one of the Midwest's premier shopping destinations and a dense cluster of company headquarters. Auburn Hills, further north, carries the county's automotive engineering legacy forward, home to a major automaker's global headquarters and a growing university presence.

How to dial a 948 number

Because 948 and 248 overlay the same territory, every call placed within Oakland County — even between two homes on the same street — must include the area code.

Seven-digit dialing has not worked in Oakland County since the overlay took effect. The region runs on Eastern Time — Eastern Standard Time (UTC−5) in winter and Eastern Daylight Time (UTC−4) in summer, the same clock as Detroit and New York. At noon in Troy it is 11 AM in Chicago, 10 AM in Denver, and 9 AM in Los Angeles. On the same Eastern Time clock, the 586 area covers neighboring Macomb County in the Detroit metro under its own dedicated prefix.

Why choose a 948 number

A 948 number places a business inside one of Michigan's wealthiest and most business-dense counties, without requiring office space in Troy, Southfield, or anywhere near Detroit. Local numbers earn higher answer rates than out-of-area codes, and a 948 or 248 prefix reads as "local" to Oakland County residents, even though most callers can't tell the two codes apart.

That local read matters for professional services firms, automotive suppliers, and remote teams serving Oakland County clients without a physical office there. A virtual provider issues the number and forwards calls to whatever device is already in use — a mobile phone, a desk line, or a softphone app. My Country Mobile can activate a 948 number the same day, letting a business start answering as a local Oakland County line immediately.

Staying safe from 948 scam calls

Overlay regions like 948/248 are a favorite target for spoofing, since the sheer volume of legitimate corporate and residential numbers using both codes makes a faked caller ID easy to blend in. Common scams include fake utility disconnection notices, impersonation of Oakland County government offices, and "neighbor spoofing" robocalls designed to look like they're coming from a nearby address.

Carriers increasingly rely on the FCC's STIR/SHAKEN framework to flag likely spoofed calls, which is why some incoming 948 numbers now show up automatically labeled "Spam Risk" or "Scam Likely." Even so, the safest habit is manual verification: if an unexpected 948 caller pressures you for payment, gift cards, or personal details, hang up and call the organization back on a number you already trust.

Conclusion

The 948 area code exists because Oakland County's corporate, automotive, and residential growth simply outpaced what 248 could hold on its own. Sharing its entire footprint with 248, it now covers corporate towers in Southfield, automotive campuses in Auburn Hills, retail hubs in Troy, and some of Michigan's most established suburbs — all under a single mandatory 10-digit dialing rule.

For businesses, that density is an advantage: a 948 number puts you inside one of the Midwest's strongest local economies instantly, with no office lease required. Whether the goal is regional credibility, remote flexibility, or a straightforward Detroit-area presence, a provider like My Country Mobile can have that number live the same day.

Key takeaways

• The 948 area code is an overlay on 248, covering all of Oakland County, Michigan.
• It spans corporate hubs like Troy and Southfield and residential suburbs like Birmingham and Bloomfield Hills.
• The overlay was layered onto 248's original 1997 footprint and made 10-digit dialing mandatory.
• 948 runs on Eastern Time, matching Detroit and the rest of southeastern Michigan.
• A local 948 number builds instant Oakland County credibility and can be activated from anywhere.
• Scammers spoof 948 numbers, so verify unexpected callers before sharing money or personal details.

Frequently asked questions