ZIP codes
137
Area Code 231
Explore ZIP codes in area code 231 — covering MI — 137 ZIP codes — 696,352 residents. Population, income, and housing at a glance.
Population
696,352
States
MI
Median household income (avg.)
$68,523
Average home value
$221,110
Where is area code 231?
Area code 231 maps to 137 indexable ZIP codes on US5 across MI, with a combined ZIP-area population of about 696,352.
Among places with the most population in this NPA on US5 are Norton Shores, MI, Muskegon, MI, Traverse City, MI, Greilickville, MI, and Cadillac, MI. Open any ZIP below for full demographics, housing, and nearby services.
The most populous ZIP currently listed for 231 is 49442 (about 44,412 residents).
Income and housing in 231
Across ZIPs with income data in area code 231, the average median household income is about $68,523 — about 9% below the U.S. median ($75,149).
Average median home value across those ZIPs is about $221,110.
On this page’s income ranking, ZIP 49628 is near the top at about $125,938.
How area code 231 numbering works
In the North American Numbering Plan, the first three digits of a 10-digit phone number are the Numbering Plan Area (NPA), commonly called the area code. Digits 4–6 are the central office code (NXX / “exchange”), and the last four digits identify the individual line.
US5’s 231 page groups ZIP codes that are associated with this NPA in published geography data. That is a place-based view — it is not a live directory of every phone number assigned to 231, and overlays or split NPAs can mean multiple area codes serve the same metro.
Scams and caller ID spoofing
Seeing area code 231 on caller ID does not prove the caller is physically in MI. Spoofing tools can display almost any NPA, including local-looking numbers used in IRS, bank, warranty, and “grandparent” scams.
If you receive an unexpected call about taxes, arrests, or locked accounts: hang up, do not share codes or remote-access software, and contact the organization using a number from its official website or your statement — not a number the caller provides. US5 publishes geography for research; it does not verify live callers.
ZIP codes in area code 231
Frequently asked questions
Where is area code 231?
Area code 231 is associated with ZIP codes in MI on US5, covering about 696,352 combined ZIP-area residents across 137 codes. Browse the ZIP table on this page for cities and counties.
How many ZIP codes are in area code 231?
US5 currently lists 137 indexable ZIP codes for area code 231. Counts can change as geography publishes update.
What is the average income in area code 231?
The average of ZIP median household incomes in area code 231 is about $68,523 (about 9% below the U.S. median ($75,149)). Individual neighborhoods vary — sort the ZIP table by income to compare.
What is an NXX or “number block” in area code 231?
After the area code, the next three digits (NXX) identify a central office / exchange “block” of up to 10,000 numbers. US5 focuses on ZIP geography for 231; for live number assignment details, use official NANPA / carrier resources.
Does a 231 caller ID mean the person is local?
No. Caller ID can be spoofed to show area code 231 even when the caller is elsewhere. Treat unexpected calls about money, arrests, or account lockouts as suspicious and verify through official channels.
How can I avoid phone scams that use area code 231?
Do not trust caller ID alone. Never send gift cards, wire money, or install remote-access apps because a caller claims to be from the IRS, a bank, or tech support. Hang up and call back using a published number from a statement or official website.
What cities use area code 231?
Larger population clusters on US5 for 231 include Norton Shores, MI, Muskegon, MI, Traverse City, MI, Greilickville, MI, and Cadillac, MI. Open linked ZIP pages for neighborhood-level demographics.