I live in South Louisiana, which isn't exactly a hot-bed of celtic culture...
Check out these folks just down the road:

www.celts1.com (Celtic Society of La.)

http://www.angelfire.com/la2/sasbr/ (St. Andrew's Society of Baton Rouge)

http://www.csbr.org/ (Caledonian Society of Baton Rouge)

And one just for fun: http://home.netcom.com/~rsbo/cajun.htm

I know several of them -- great bunch of people! And all three groups were instrumental in getting official recognition of the Louisiana State Tartan.

My wife's people are Melancons.

Cheers,

Todd (Cajun by the ring & back-door!)