There are nine species of yellow violets that are found in our area and they are not always easy to tell apart, but I am reasonably certain that this is the Evergreen or Redwood Violet, Viola sempervirens. It was photographed along the Westside Road in Mount Rainier National Park this past spring. We were too early for most of the wildflowers, but did find these and a few others.

ronaldhanko-orchidhunter.blogspot.ca/2012/05/mount-rainie...