There are sites you can find on google that will give you the geolocation of an ip address... although this may not always be accurate.
Is a pretty fair one.
Could always whois the ip range at arin or the domain name and see where it's registered too although that isn't necessarily accurate.
Keep in mind, physical proximity does not necessarily indicate faster speeds. I had a site I could have used sneaker net with take 18 hops to and from and manage to get all the way to Texas. I've had sites across the country be 10 hops away and give me a ping time and speeds that made me smile.
If you have a fast connection, pick any one at random that looks like it might be regional and give it a go, if it seems slow after 2-3m pick a different one.
It's really not worth worrying about all that much.