Limit to Just U.S. Visitors?

Again — this map shows really nicely and the plugin works great.

My question — I’m trying to figure out how to have this map limit to U.S. visitors. I’m at a nonprofit that works just in in 48 states and want to focus on just that area.

I’ve edited the code for a couple of other things, and now I’m looking to make that edit as well.

Thank you.