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  3. Area code 423
Tennessee (TN)Eastern Time (ET), Central Time (CT)

Area Code 423

Tennessee (TN) * Chattanooga, Johnson City, Kingsport, Cleveland, Greeneville, Morristown, Afton, Apison * Eastern Time (ET), Central Time (CT)

1.5M

Population

151

ZIP codes

Tennessee

Primary state

Eastern Time (ET), Central Time (CT)

Time zones

What stands out

  • Coverage: 1.5M people across 151 ZIP codes.
  • Major cities: Chattanooga, Johnson City, Kingsport.
Primary state:Tennessee (TN)/Major cities:Chattanooga, Johnson City, Kingsport, Cleveland, Greeneville, Morristown, Afton, Apison

Browse sections

Basics

Percentiles compare this area code to other area codes nationwide.

Population

1.5M

ZIP codes

151

Median age

42.3 yrs

Population density

155.4/sq mi

Mean commute time

25 min

Avg. household size

2.4

Neighbors

Neighboring area codes

256276336606706743762828865931938
Notes & Sources
  • Area-code boundaries can change over time; verify official assignments with NANPA for critical use.
  • This page aggregates ZIP-based crosswalks for orientation and does not indicate phone-number availability.

Data freshness

ACS 5-year
2020–2024
Page updated
2026-02-23

Release schedule and upstream dates: Sources.

Data sources

U.S. Census (ACS 5-year)U.S. Census TIGER/LineNANPA

Derived statistics

  • Area codes are not Census geographies; statistics are estimated by aggregating ZCTA (ZIP) values for associated ZIPs.
  • ZIP↔area code associations are derived from NPA boundary polygons and ZCTA centroid points, and can be approximate.
  • Median age, mean commute, and household size are population-weighted; population density uses summed ZIP land area.
Area code overlays and service areas are primarily governed by NANPA; this page uses aggregated geographic overlays for orientation only.

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.