At my children's (and granddaughter's) school it went something like this.
Graduation ceremony at the sports arena. Grads wore cap and gown. Long, rather boring ceremony with speeches from principal, guest speaker, valevictorian, others; band, school song, announcements of scholarships and awards, then the walk across the stage as names were called and (fake) certificates handed out. (They picked up the real ones during the following week.) Then the parents met at the school gym for a meet and greet and the grads boarded buses for their safe-grad party.
The safe-grad party was held at a summer camp on a lake 60 klms away and down a gravel road. Absolutely no drinking or drugs (considered uncool to even try to sneak any in). All night bar-b-q, beach volleyball, campfire, music, swimming, running around. I knew one boy who took along his fishing rod, walked along the water's edge away from the noise to sit on a rock and fish.
Supervision by volunteers - teachers and parents.
The buses returned in the wee hours to get the kids back home, exhausted.
The prom was on a different night. Grads and dates gathering at the upper parking lot of the university to assemble for the prom parade. Well wishers gathered on either side of the road. First came the walkers - girls in formal dresses, guys in suits or tuxes, then bicycles, rickshaws, sometimes a horse-drawn buggy, motorcycles, trucks, cars, limos. The dance seemed anti-climatic after the parade. Then kids went to private parties - or out to dinner in a fancy restaurant with their parents, or just went home.
Both our kids and granddaughter went to the Grad. Seelerboy skipped the parties and prom - but he did escort his sister's friend to her prom the next year.