ZIP codes
271
Area Code 815
Explore ZIP codes in area code 815 — covering IL — 271 ZIP codes — 1,788,072 residents. Population, income, and housing at a glance.
Population
1,788,072
States
IL
Median household income (avg.)
$79,099
Average home value
$176,687
Where is area code 815?
Area code 815 maps to 271 indexable ZIP codes on US5 across IL, with a combined ZIP-area population of about 1,788,072.
Among places with the most population in this NPA on US5 are Rockford, IL, Joliet, IL, Crystal Lake, IL, Plainfield, IL, and DeKalb, IL. Open any ZIP below for full demographics, housing, and nearby services.
The most populous ZIP currently listed for 815 is 60435 (about 48,521 residents).
Income and housing in 815
Across ZIPs with income data in area code 815, the average median household income is about $79,099 — about 5% above the U.S. median ($75,149).
Average median home value across those ZIPs is about $176,687.
On this page’s income ranking, ZIP 60072 is near the top at about $153,542.
How area code 815 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 815 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 815, and overlays or split NPAs can mean multiple area codes serve the same metro.
Scams and caller ID spoofing
Seeing area code 815 on caller ID does not prove the caller is physically in IL. 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 815
Frequently asked questions
Where is area code 815?
Area code 815 is associated with ZIP codes in IL on US5, covering about 1,788,072 combined ZIP-area residents across 271 codes. Browse the ZIP table on this page for cities and counties.
How many ZIP codes are in area code 815?
US5 currently lists 271 indexable ZIP codes for area code 815. Counts can change as geography publishes update.
What is the average income in area code 815?
The average of ZIP median household incomes in area code 815 is about $79,099 (about 5% above 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 815?
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 815; for live number assignment details, use official NANPA / carrier resources.
Does a 815 caller ID mean the person is local?
No. Caller ID can be spoofed to show area code 815 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 815?
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 815?
Larger population clusters on US5 for 815 include Rockford, IL, Joliet, IL, Crystal Lake, IL, Plainfield, IL, and DeKalb, IL. Open linked ZIP pages for neighborhood-level demographics.