Along the northern tier of the country (the Dakotas, Wyoming, Montana, Idaho, Washington and I think Oregon), everything is counted one side at a time.
That includes whitetail, muleys, elk, even the jackalope in the bar, as long as it has antlers and not horns.
I have lived in eastern North Dakota, along the Minnesota border, and you will find a few Dakotans there who use the eastern count but not many. Drive across the river into Minnesota, however, and it is strictly eastern count, at least in my experience.
In northern California we just count one side also.
Fargo? Grand Forks? Moorhead is my old homestead. Thinking about returning after more than 40 years in the warmer climes...