WHAT
Scattered throughout the 922,810 acres that comprise Olympic National Park are over 650 lakes and wetland areas, which act to regulate the flow and dispersal of water. These water bodies—home to fish, reptiles, insects, birds and aquatic associated mammals and plants—are beautiful to the point of rendering insufficient most attempts to describe them. Beyond scenic, they critically support the old growth forest ecosystem and all that inhabit those environmental communities.
WHERE
ONP has only four lowland lakes. The two largest are Lake Ozette, at the northern end of the Parks Coastal strip (ranked as the second largest natural lake in Washington state) and Lake Crescent on US 101, 30 minutes west of Port Angeles (ranked at number five). 
Though they are large, astonishingly beautiful and easily accessible in every season, they are also distinctly different. Lake Crescent is the result of glacial action. (The Frazier Glacier, originating in Canada as part of the Late Wisconsin glaciation of the Pleistocene Epoch, covered the northern portion of the Olympic Peninsula in 4000 feet of slowly moving ice, advancing and retreating repetitively over thousands of years). That action carved Lake Crescent to a depth of over 600 feet. Unlike Lake Crescent, Lake Ozette was created by tectonic-plate collisions, also called Orogenic uplifting of the Olympic peninsula. Literally having risen from the sea, Lake Ozette is relatively shallow and stands only 33 feet above sea level.
WHEN
There are over 300 high mountain lakes in the Park, accessible only in summer and the early fall. Seventeen of these can be reached as day hikes of various length and difficulty. However, one of these, Lake Constance, exists at the outer edge of both categories. The trailhead is at the end of the Dosewwllips Road (N47 43.850 W123 05.427). The hike is short— at only five miles one way—but it is difficult in the extreme, laying claim to the title of the Park’s steepest trail. It gains an astounding 3250 vertical feet in the last two miles, an unrelenting ambition-crushing grade of 30%. Not a trial for the faint of heart!
WHY
Each alpine lake is a jewel and a joy unto itself, perched in a setting of awe-inspiring beauty. Here are two of 300 possible examples: Royal Lake, in the Dungeness drainage, reflects the image of Mounts Deception and Mystery and also The Needles in homage to these three sentinels silently standing guard above her. Hoh Lake, perched on a ledge nearly 4000 vertical feet above the Hoh valley, has an unobstructed world-class view of the 7076 ft. summit of Mt. Olympus, eight miles to the SE.
All the high mountain lakes reside in areas designated Primitive or Primeval Wilderness. Unspoiled, they beckon hardy travelers with their serene beauty and unique location. Given the care and respect they deserve by those fortunate enough to visit, they will remain precious objects of wonder, undiminished by the passing attention of visitors as they have for thousands of years.