What is a Class 2 Historic site?

Question:

What is a Class 2 Historic site?

My nephew's wife has found a Class 2 Historic site with the name of a family I'm doing genealogical research on. What is a Class 2 Historic site?

Best Answer - Chosen by Asker: It's not a US term so far as I've ever seen. If any of the 50 US States use that term I haven't seen it either but it's not impossible.