Prairie Rattlesnake

Thanks Ashley for the updated information!

Crotalus viridis oreganus, as you have this species listed as, does not exist anymore. And it hasn't for quite awhile. C. oreganus is the Northern Pacific Rattlesnake (which this is not), and C. viridis is the Prairie Rattlesnake. C. viridis can also be referred to as the Western Rattlesnake, but that name is more commonly used for C. oreganus. Please update this spotting accordingly.

I looked at your image a bit closer. It looks like your snake has big pits on the face (and the color pattern on the head), and that points to rattlesnake. There appears to only be one species of rattlesnake in your area.