My hunting/fishing buddies and I discovered a new blooper when we were traveling in Wyoming over Independence Day. Riverton does not have a fireworks celebration on the Fourth, and hasn't had one for over 20 years. That's because fireworks are put on by Lander, 20-odd miles to the southeast where the county seat is and where there is a rodeo beforehand. Riverton hosts the 1839 Rendezvous of the mountain men over that weekend instead. It's a gathering where people stage a recreation of a historic camp, along with demonstrations of shooting, butter churning, and that type of thing.
I suppose the celebration that Ennis and Alma went to could have been in Lander, but it doesn't seem likely.