If your machine is connected to a domain, you can use PowerShell to identify the domain controller you are connected to. Either use this command:
Get-ADDomainController -Discover
Or, simply look up the “LOGONSERVER” environment variable:
$env:LOGONSERVER
It lists the name of the computer that you logged on to. If it is equal to your own computer name (without the backslashes), then you are logged on locally and not to a domain:
if ($env:LOGONSERVER.TrimStart('\') -eq $env:COMPUTERNAME) { "local" } else { "logged on to $env:LOGONSERVER" }