Olympic doesn’t have level of notoriety as Yellowstone or Yosemite, but perhaps it should. It is one of the most visually stunning and unique national parks in all of North America.
Located in the Olympic Peninsula, it isn’t located near any large metropolitan areas which reduces the number of tourists. The Olympic Mountains aren’t the largest mountains, but their location along the Pacific Coast means that they get a tremendous amount of rain and snowfall.
The eastern slope of the mountains are much like any mountain area you would find in the Rockies or Sierras. The western slope, however, gets a tremendous amount of rain, which makes that region one of the few temperate rainforests in the world. The trees (and everything to be honest) on the western side are covered in moss which flourishes in this wet environment.
This also just happens to be near the town of Forks, which is the setting of the Twilight books. Sadly, it probably attracts more vampire fans than nature fans.