How do I register a County Government DN?

[myblueshoes]

www.co.hunterdon.nj.us/

I need to register a DN like the one above (but not this one) for a new county government website. How do I do do it? It's not just a .US w/ a subdomain is it?

is the DN just, "co.hunterdon.nj" with a .us extention?

Any help appreciated.