Country and Bluegrass music are sorta cousins. They share a lot of the same instruments, and have a lot in common, yet they can be completely different. For instance a lot of Country music involves electric guitars and drums.
You won't find either of those in Bluegrass.
Bluegrass is almost exclusively acoustic instruments. Being a huge acoustic guitar fan, that's why I'm happy to hear that the Sixth Annual Wichita Falls Bluegrass Festival is coming soon!