How do I connect to a local host using PrincipalContext?

I know this has a simple solution, but I can't seem to make it work...

Using other Stack Overflow answers and Microsoft's Documentation, I know that PrincipalContext must be set up like this:

PrincipalContext pc = new PrincipalContext(ContextType.Domain, "YOURDOMAIN"); 

or also like this:

PrincipalContext domainContext = new PrincipalContext(ContextType.Domain,"YOURDOMAIN", null,ContextOptions.Negot开发者_开发问答iate | ContextOptions.SecureSocketLayer);  

My question is, what do I put for the "YOURDOMAIN" attribute if I am connecting to a local host?

Trying this ended in a PrincipalServerDownException:

PrincipalContext pc = new PrincipalContext(ContextType.Domain, "localhost:3600")

Is this what you're looking for? :

   PrincipalContext pc = new PrincipalContext(ContextType.Machine, null);