Many towns founded by Germans have Oktoberfests. Reportedly, the one in Frankenmuth, Michigan is one of the best and is the only Oktoberfest officially sanctioned by the City of Munich outside of Germany. Others of note are held in Hermann, Missouri, New Ulm, Minn., Fredericksburg, TX ,and La Cross, WI. Most are held in late Sept. but some are held in October. The only one I've been to was in Hays, Amerika (KS). Lots of good German food and bier.

They have a lot in Pennsylvania and Ohio, of course. I think the ones in Cleveland, Cincinnati and Reading, PA are supposed to be major. USA Today has a list of their 10 best if you google that 10bestusa.com/awards/best-octoberfest. I'll admit I've never been to one even though I have German heritage as I don't like beer that much.

I have German heritage too and no longer care for beer but they can still be fun (sometimes Polka dancing). German food overall isn't that great but I sure like Bierocks (cabbage rolls).

Central Texas has many towns that were founded by Germans and the German heritage lives on. The OP already mentioned Fredericksburg, TX. There's an October German festival in New Braunfels, TX called Wurstfest. There's also Deutschen Fest in Pflugerville, TX just outside Austin.