Validate Two Letter Region Names with PowerShell

ValidateTwoLetterRegionName.ps1

$TwoLetterISORegionNames = Get-Culture -ListAvailable |
    Foreach-Object {
        try { [System.Globalization.RegionInfo]::new($_.Name) }
        catch {}
    } |
    Select-Object -ExpandProperty TwoLetterISORegionName | Sort-Object -Unique

'US','CA','UK' | % { $_ -in $TwoLetterISORegionNames ? '{0} is valid' -f $_ : '{0} is not valid' -f $_ }