North American Numbers Source-cited · ownership disclosed
Area code
353
In service
United States · since 2023

Madison (overlay)

An overlay of area code 608 covering the same southwestern Wisconsin geography (Madison and surrounds), added because of rapid prefix growth in Dane County. In service in 2023.

The essentials Numbering data · NumberResearch · as of 2026-09-18
Place
Madison (overlay)
Type
geographic
Status
in service
In service since
2023
Projected exhaust
2065 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 353 is

Same as 608 — 19 counties of southwestern Wisconsin including Dane, Rock, La Crosse, Grant, Sauk, Columbia..

Communities served wholly or partly by 353:

MadisonJanesvilleLa CrosseBeloitWisconsin DellsBaraboo

Cities are shared with 608; 353 numbers are assigned across the whole 608 footprint.

B · Relationships

How it relates to other codes

The codes 353 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?

Overlay · 2023 608 Madison Overlays the entire 608 numbering plan area.
What's changing. Overlay of 608. Assigned 2023 — re-check NANPA for current fill/status.
C · History

How 353 got here

2022-09
Overlay complex announced.
Source: Wikipedia
2023-09-15
Placed in service as overlay of 608 (date UNVERIFIED — see 608 note).
Source: Wikipedia
D · Capacity

How full it is

Prefixes assigned
27
Prefixes available
773
Thousands-blocks assigned
61

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

Compare 353 with another code →
Sources
Wikipedia ↗
Area code 353
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.