(It varies, depending your location)

In America, I'm considered a young adult. I'm 23 years old And I went trick or treating until I was 18. After that, there are a lot of frat parties in universities where fraternities throw parties and everyone has to wear a costume or is not admitted into the party... I've been to this kind of parties it gets pretty wild.

now if you are a post graduate, you would go out to theme parks where everything is decorated for halloween, and they have actors dressed as zombies walking around scaring people. Six flags has this event every year. Oh and how can I forget, there is a huge halloween parade in NY that night, where everyone goes and then after the parade they go to bars decorated for that night.  Now if you are older than 30 and have kids, they usually watch scary movies , like Friday 13 And prepare the candy for the kids coming out at night. Or go out to fancy parties with masks only. Hope this helped..