Area Code 815

Illinois (IL) • Rockford, Joliet, Plainfield, Crystal Lake, Mchenry, Amboy, Ancona, Apple River • Central Time (CT)

What Stands Out

•Coverage: 1.7M people across 263 ZIP codes.
•Overlapping area codes: 779.
•Major cities: Rockford, Joliet, Plainfield.

Spotlight: Coverage

Snapshot highlights for area code 815.

Income

69th

Home values

51st

Poverty rate

52nd

Area Code Basics

Primary State

Illinois (IL)

States Served

Illinois (IL)

Major Cities

Rockford, Joliet, Plainfield, Crystal Lake, Mchenry, Amboy, Ancona, Apple River

Time Zone(s)

Central Time (CT)

Est. Population

1.7M

ZIP Codes

263

Data accuracy & methodology

This report aggregates 2020–2024 ACS 5-year estimates and geographic overlays for orientation. Area-code service areas can cross ZIP/state boundaries and change over time; verify official assignments with NANPA for critical use.