Area Code 618

Illinois

Area code 618 serves Illinois, primarily Belleville, in the Central Time (CT) time zone. It has served the region since 01-Jan-1947.

Published: February 17, 2026Verified against NANPA and FCC records

Overlay Area Code

This area code shares its geographic footprint with an overlay code, so the same cities are served by two area codes. Because overlays leave existing numbers untouched, this region's relief planning favors adding codes over redrawing boundaries.

The codes serving this same region: area code 730 (Belleville).

With prefix utilization already at 98.3%, numbering resources here are under sustained pressure — context that explains why overlays were introduced.

In service since: 01-Jan-1947

Learn more about overlay and split area codes →

Demographics & Economics

Total Population: 1,806,463
Population Density: 61 people/sq mi
below U.S. average (U.S.: 95 people/sq mi)
Median Household Income: $71,674
below U.S. median (U.S.: $80,734)
Poverty Rate: 13.4%
near U.S. average (U.S.: 12.5%)
Unemployment Rate: 5.0%
near U.S. average (U.S.: 5.2%)
Education Attainment: Bachelor's Degree+
25.2%
below U.S. average (U.S.: 35.7%)
High School or Lower
33.7%

Statistics are population-weighted aggregations from Census ACS 5-year estimates. Population figures are approximate — see Sources & Methodology for details on how area code populations are derived.

See how this area code compares to all US area codes in the income ranking and density ranking.

Time Zone

Central Time (CT)

NANPA Relief Status

According to the latest NANPA analysis (July 2026), this area code is not currently listed as exhausting within the next 36 months. No relief planning is in progress for this NPA.

Source: NANPA NPA Relief Planning Reports · See all relief planning statuses

Current Time

Central Time (CT)

Prefix Utilization

Geographic Coverage

State

Major Cities

Belleville
O'Fallon
Granite City
Edwardsville
Alton
Collinsville
Carbondale
East St. Louis
Godfrey
Cahokia Heights
Marion
Fairview Heights
Swansea
Mount Vernon
Shiloh
Glen Carbon
Herrin
Centralia
Columbia
Waterloo
Troy
Wood River
Highland
Bethalto

and 312 more cities

Area Code 618 geographic coverage map (light mode)

Demographics

The estimated population served by area code 618 is approximately 1,806,463. The population density is 61 people per square mile, which is lower than the national average of 95. The median household income is $71,674, which is lower than the national median of $80,734. Approximately 25.2% of adults hold a bachelor's degree or higher, compared to the national rate of 35.7%. This rate is lower than the national average. The poverty rate stands at 13.4%, which is near the national rate of 12.5%.

History

Area code 618 is one of the original area codes established in 1947 when the North American Numbering Plan (NANP) was created. It shares its territory with area code area code 730.

County Coverage

Population-weighted county share based on aggregated ZCTA population (100% = total mapped population for area code 618).

County	Population	Share
St. Clair, IL	339,994	18.8%
Madison, IL	303,245	16.8%
Williamson, IL	118,456	6.6%
Jackson, IL	88,609	4.9%
Clinton, IL	76,094	4.2%
Jefferson, IL	60,220	3.3%
Macoupin, IL	51,922	2.9%
Marion, IL	47,215	2.6%
Monroe, IL	45,781	2.5%
Franklin, IL	45,564	2.5%
Jersey, IL	40,728	2.3%
Washington, IL	37,365	2.1%
Randolph, IL	37,253	2.1%
Wayne, IL	37,224	2.1%
Bond, IL	33,179	1.8%
Fayette, IL	33,031	1.8%
Perry, IL	31,636	1.8%
Pope, IL	31,527	1.7%
Saline, IL	30,415	1.7%
Union, IL	28,122	1.6%
Richland, IL	26,432	1.5%
Clay, IL	25,828	1.4%
Hamilton, IL	25,825	1.4%
Crawford, IL	23,551	1.3%
Lawrence, IL	18,634	1.0%
Massac, IL	18,298	1.0%
Johnson, IL	17,171	1.0%
White, IL	15,877	0.9%
Effingham, IL	15,603	0.9%
Gallatin, IL	14,682	0.8%
Greene, IL	14,428	0.8%
Wabash, IL	13,792	0.8%
Jasper, IL	11,513	0.6%
Alexander, IL	8,757	0.5%
Pulaski, IL	8,209	0.5%
Edwards, IL	7,561	0.4%
Hardin, IL	6,288	0.3%
Shelby, IL	5,445	0.3%
Calhoun, IL	4,099	0.2%
Clark, IL	3,198	0.2%
Montgomery, IL	3,056	0.2%
Cumberland, IL	636	0.0%

Area Code 618 Family Tree

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Total Codes

Splits

Overlays

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All Descendants

Code ▲	State	Type	In Service	Parent
730	IL	overlay	07-Jul-2023	618

Area code 618 was originally assigned in 01-Jan-1947 to serve IL. Over the years, it has generated 1 descendant area code through a combination of geographic splits and overlays as demand for telephone numbers grew.