North American Numbers Source-cited · ownership disclosed
Area code
586
In service
United States · since 2001

Macomb County

Macomb County (northeast Metro Detroit), created by a 2001 split of area code 810 after strong local opposition to an overlay proposal.

The essentials Numbering data · NumberResearch · as of 2026-09-18
Place
Macomb County
Type
geographic
Status
in service
In service since
2001
Projected exhaust
2082 Q1

Status, dates and counts are read from NumberResearch (NANPA / CNAC / FCC records). Assignment records show initial assignees, not the carrier serving a number today.

A · Where it is

Where 586 is

Macomb County, Michigan..

Communities served wholly or partly by 586:

WarrenSterling HeightsSaint Clair ShoresRosevilleMount ClemensUticaClinton Township
B · Relationships

How it relates to other codes

The codes 586 was split from, spawned, or shares its area with. A split divides the map and changes some numbers; an overlay shares the same ground and changes none — what's the difference?

Split from · 2001 810 Flint / The Thumb Split from 810.
Related 248 Oakland County Oakland County (248/947) to the west.
Related 313 Detroit Detroit/Wayne County to the south.
What's changing. No overlay; single code for Macomb County.
C · History

How 586 got here

2000
Initially proposed as an overlay of 810; dropped after intense opposition to 10-digit dialing.
Source: Wikipedia
2001-09-22
Implemented as a split from 810, giving most of Macomb County the new code.
Source: Wikipedia
D · Capacity

How full it is

Prefixes assigned
570
Prefixes available
230
Thousands-blocks assigned
2,831

Prefix-assignment counts describe allocation to carriers, not how many individual numbers are in use. Full technical records: NumberResearch ↗.

Compare 586 with another code →
Sources
Wikipedia ↗
Area code 586
NumberResearch.org ↗
Live status, dates, assignment counts and exhaust forecast — data as of 2026-09-18 (CC BY 4.0).

Place, relationships and history above are compiled by North American Numbers from the sources listed and last checked 2026-09-18. A check date is not an expert review — see how this is made. Flag an error.