The value of this property, also called "metro code" depends on the countries involved. Below you will find the detail for each country:
- United States: The standard for US metro areas is Nielsen Direct Market Areas (DMAs). All US cities fall into a DMA and DMAs may cross state lines. If ANY part of a state falls into a DMA, then that state is listed in the regions. If parts of multiple states fall into a DMA they are separated by a /. Within the sub-region value, multiple cities are separated by a / as well.
- United Kingdom: The standard used for the metro areas in United Kingdom is based on ITV regions. Following ISO-3166-2 standardization in October 2012, the regions list for a metro/ITV area in the UK grew quite large.
- France: The metro codes for France reflect the Departments of France.
- Germany: The metro codes for Germany reflect the Neilsen TV markets.
- South Korea: The metro codes for South Korea use the Municipal level divisions si, gun, and gu. See Administrative divisions of South Korea for explanation of si, gun, and gu.
- China: The metro codes for China use the diji shi administrative definition of prefecture-level cities administered at the provincial level and also include the four zhixia shi (Beijing, Tianjin, Shanghai, Chongqing) administered by the Central Government.
- Russia: The metro codes for Russia are based on the Russian Federal Districts. Please note that 1 of the 9 districts is defined as Crimea, which is currently disputed between Ukraine and Russia. Although the Russian government recognizes Crimera as part of Russia, including it as a Federal Districts, the ISO standard used for country/region level targeting recognizes Crimea as part of Ukraine. Crimea is listed with country of rus and region 43, the ISO region code response for Crimea in Ukraine.
- Canada: The metro codes for Canada are based on the Canadian Census Metropolitan Areas (CMA). This standard defines the boundary definitions and which cities are located within each area. As such, some Canadian cities will not have an associated metro code when they don't fall into one of these CMAs.
- Norway: The metro codes for Norway are based on the Norwegian municipalities, most commonly referred to as "Kommunes".
- New Zealand: The metro codes for New Zealand are based on the urban areas of New Zealand defined by Statistics New Zealand.
- Australia: The metro codes for Australia are based on the Greater Capital City Statistical Area (GCCSA) and Significant Urban Area (SUA) defined by the Australian Bureau of Statistics. This standard defines the boundary definitions and which cities are located within each area. As such, some Australian cities will not have an associated metro code when they don't fall into one of these GCCSA/SUA areas.
- Finland: The metro codes for Finland are based on the Finnish municipalities.
- Aland Islands: The metro codes for Aland Islands are based on the Finnish municipalities.
- Japan: The metro codes for Japan are based on the metropolitan areas from the Statistics Bureau of Japan.
- Denmark: The metro codes for Denmark are based on the municipalities of Denmark.
- Iceland: The metro codes for Iceland are based on the municipalities of Iceland.
- Sweden: The metro codes for Sweden are based on the municipalities of Sweden.
- India: The metro codes for India are based on the Municipalities or Panchayats assignments by the India Ministry of Statistics and Programme Implementation.