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Michigan (MI)Eastern Time (ET)

Area Code 231

Michigan (MI) * Muskegon, Traverse City, Afton, Alanson, Alba, Alden, Arcadia, Bailey * Eastern Time (ET)

698.3K

Population

136

ZIP codes

Michigan

Primary state

Eastern Time (ET)

Time zones

What stands out

  • Coverage: 698.3K people across 136 ZIP codes.
  • Major cities: Muskegon, Traverse City, Afton.
Primary state:Michigan (MI)/Major cities:Muskegon, Traverse City, Afton, Alanson, Alba, Alden, Arcadia, Bailey

Browse sections

Basics

Percentiles compare this area code to other area codes nationwide.

Population

698.3K

ZIP codes

136

Median age

44.4 yrs

Population density

75.5/sq mi

Mean commute time

23 min

Avg. household size

2.4

Neighbors

Neighboring area codes

616989
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.