---
title: "Area code 815: Illinois, United States"
url: "https://lookvalid.com/area-code/815.md"
canonical_url: "https://lookvalid.com/area-code/815"
last_updated: "2026-10-23"
type: "reference"
summary: "Area code 815 serves Illinois, United States. Number formats, numbering rules, a live phone validator and the other codes in Illinois."
---

# Area code 815: Illinois, United States

Area code 815 serves Illinois, United States. Number formats, numbering rules, a live phone validator and the other codes in Illinois.

NANPA lists 786 central office codes (prefixes) in use in area code 815, held by 53 holders across 200 rate centers.
Illinois Bell Tel holds the most prefixes, 157 (20%). 66% of the prefixes are pooled, which means their thousands-blocks can belong to different companies.
The FCC unwanted-call data has 2,632 complaints on file for 2,174 numbers in 815, most often filed as "Unwanted Calls". These are consumer reports, not findings.

## Facts

- In service since: 1947-01-01
- Time zone: Central (C)
- Assigned overlays: 779 (2007-03-17)
- Prefixes in use: 786
- Pooled prefixes: 519 (66%)
- Rate centers: 200
- Companies holding prefixes: 53
- Assignment dates on file: 2001-01-24 to 2025-05-16 (182 prefixes)
- ZIP codes in its places: 193

## Rate centers

| Rate center | Prefixes | Share |
| --- | --- | --- |
| ROCKFORD | 89 | 11% |
| JOLIET | 62 | 8% |
| KANKAKEE | 33 | 4% |
| WOODSTOCK | 28 | 4% |
| DE KALB | 24 | 3% |
| FREEPORT | 18 | 2% |
| LOCKPORT | 18 | 2% |
| MCHENRY | 18 | 2% |
| 192 other rate centers | 496 | 63% |

## Carriers

| Holder | Prefixes | Share |
| --- | --- | --- |
| Illinois Bell Tel | 157 | 20% |
| Frontier North | 133 | 17% |
| Level 3 Communications | 76 | 10% |
| Verizon Wireless | 50 | 6% |
| Aero North Communications | 43 | 5% |
| New Cingular Wireless PCS | 42 | 5% |
| 47 other carriers | 285 | 36% |

A prefix holder is the company a code was assigned to, not necessarily a number's current carrier, because numbers can be ported to another company.

## History

- 1947-01-01: Area code 815 went into service.
- 2007-03-17: Area code 779 went into service as an overlay in the same area as 815.

## Nearest area codes

The area codes closest to 815, measured between the centers of the ZIP code places they serve, are 331 (about 34 miles), 630 (about 36 miles), 312 (about 52 miles), 708 (about 54 miles) and 464 (about 56 miles).

## ZIP codes

193 ZIP codes fall in places that have a rate center in this area code. The places with the most are Rockford, IL (14 ZIP codes), Joliet, IL (6 ZIP codes) and Crystal Lake, IL (3 ZIP codes). A ZIP code and an area code are unrelated systems, so a ZIP code can sit in more than one area code and an area code spans many ZIP codes.

## Complaints on file

2,632 complaints for 2,174 numbers. Numbers whose latest complaint falls in each year:

- 2023: 147
- 2024: 111
- 2025: 203

## Questions

### Where is area code 815?

NANPA assigns area code 815 to Illinois, United States.

### In which state does area code 815 sit?

Illinois. 815 is one of 17 area codes the NANPA table assigns to the state.

### Which places does area code 815 cover?

The places with the most ZIP codes among the rate centers in 815 are Rockford, IL, Joliet, IL and Crystal Lake, IL. The rate center list on this page shows all of them.

### Who owns area code 815?

NANPA assigns area codes. Within 815, Illinois Bell Tel holds the most prefixes, 157 prefixes or 20%.

### Which time zone does 815 use?

The NANPA NPA report lists the time zone for 815 as Central (C).

### What year did 815 enter service?

The NANPA NPA report gives an in-service date of 1947-01-01, so 815 has been in use since 1947.

### Does area code 815 have an overlay?

Yes. 779 (in service 2007-03-17) shares the same area with 815, so numbers from all of them are local to each other.

### Which area codes are nearest to 815?

The area codes closest to 815, measured between the centers of the ZIP code places they serve, are 331 (about 34 miles), 630 (about 36 miles), 312 (about 52 miles), 708 (about 54 miles) and 464 (about 56 miles).

### How many prefixes does area code 815 have?

NANPA's report dated 2026-10-17 lists 786 prefixes in service in 815, spread over 200 rate centers and 53 holders.

### Are there complaints about 815 numbers?

The FCC data on file has 2,632 complaints for 2,174 numbers in 815. They are unverified consumer reports. A number with no complaints on file is not proven safe.

Sources: NANPA central office code report dated 2026-10-17; NANPA NPA report dated 2026-10-18; FCC unwanted-call complaints, data fetched 2026-10-17; ZIP code places from GeoNames (CC BY 4.0).