We recommend that you use the culture name—for example, "en-US" for English (United States)—to access the RegionInfo.NativeName property. The string used for this property depends on the language associated with the country/region. For example, the culture names en-US for English (United States) and es-US for Spanish (United States) can retrieve different values on Windows Vista. Therefore, creating the RegionInfo object with only a country/region name of US is not specific enough to distinguish the appropriate string.