Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
This one looks more like a Chloroperlidae than Capniid. Take a look at the glossae and paraglossae, the length of the cerci, and the wingpads. It's probably Sweltsa sp. based on the hairy chest/shoulders/armpits and the hairs on the cerci.