Metro dimension
Metro is the geography dimension that maps a visitor to a designated market area (DMA) — the media-market regions used in the United States. GA4 derives it from coarse IP geolocation. Because DMAs are a US construct, metro is populated mainly for US traffic and frequently reads '(not set)' elsewhere, which is expected behaviour rather than missing data.
What this means
The metro dimension assigns US visitors to a designated market area, the regional television-and-media markets advertisers plan around. GA4 derives it from the same coarse IP geolocation that feeds country and city.
For US-focused media planning it bridges analytics geography to ad-buying regions.
US-centric by design
DMAs are defined only for the United States, so metro is meaningful for US traffic and typically '(not set)' for visitors elsewhere. This is not a data gap to fix — it reflects that the concept has no equivalent outside the US.
For non-US audiences, use country, region, and city instead of expecting a metro value.
- Maps US traffic to a designated market area
- Derived from coarse IP geolocation
- (not set) for non-US traffic is expected
How it appears in analytics and logs
A metro value is a US designated market area. A '(not set)' metro for non-US traffic is normal, since DMAs only cover the United States.
Diagnostic use case
Use metro to analyse US traffic by media market, while expecting non-US traffic to return (not set) for this dimension.
What WebmasterID can help detect
WebmasterID focuses on coarse, privacy-safe geography first-party; market-level breakdowns are derived without precise location tracking.
Common mistakes
- Treating (not set) metro outside the US as missing data.
- Assuming metro applies globally like country does.
- Reading IP-derived metro as precise location.
Privacy and accuracy notes
Metro is a coarse media-market region, not a precise location or a person. WebmasterID infers only coarse geography first-party, without raw IP storage.
Related pages
- Region and city dimension
The region and city dimensions place a visit below country level — a state/region and a city — derived from IP geolocation. They look precise but are the least reliable geo tier: IP-to-city mapping is approximate, mobile and carrier routing can place a visit hundreds of kilometres off, and many visits resolve only to country, showing '(not set)' for city. Use them for rough regional skew, never as a real location.
- Continent and subcontinent dimensions
Continent and subcontinent are GA4's two broadest geography dimensions, sitting above country, region, and city. Both are derived from coarse IP-based geolocation, so they inherit its imprecision. Subcontinent uses regional groupings (such as Northern Europe or South-Eastern Asia) that do not always match colloquial expectations, which is the most common source of confusion when reading these reports.
- City-level geo accuracy and its limits
City-level geo is the lowest-confidence common geolocation tier and carries the highest privacy risk. This page explains why IP-to-city mapping is unreliable, why claiming a visitor's city is both error-prone and privacy-invasive, and why country is the responsible default.
- Privacy-first analytics
Coarse market geography without precise tracking.
Sources and verification notes
- Google Analytics Help — [GA4] Dimensions, metrics, and other termsLists the metro (DMA) geography dimension.
- Google Analytics Help — [GA4] How geolocation is derivedExplains IP-based geolocation behind metro.
Last reviewed 2026-06-24. Facts are checked against primary/official sources where available; uncertain specifics are marked “Data not yet verified” rather than guessed.