Map taken from here: Olympic Wilderness Campsite Map
The trailhead is 2 miles past the Sol Duc Hot Springs Resort. To get there from Port Angeles, go west, past Lake Crescent about 2 miles and follow the signs to the left. Fourteen miles up that winding road, following the Sol Duc River, you will arrive at the trail head.
Departing from there, you will reach the falls in about a mile. This is one of the most visited landmarks in the area, and for good reason. The combination of the mist from the falls and the sun peeking through the forest canopy makes for some spectacular pictures, despite its' relatively small size, compared to most frequently visited waterfalls.
Here is where the trail forks: Go right, towards Deer Lake or turn left, following the river and eventually reaching Heart Lake. Personally, I prefer to tackle the steep rocky climb to Deer Lake first; to come down this way after tackling the rugged terrain of the mountain can really do a number to your knees. Additionally, saving the long gradual flats of the river trail for last is a great way to cool down after the steep grades of the divide.
Assuming you take the path to the right and head towards Deer Lake, you are immediately thrust into a steep climb, seemingly endless large boulders and tree roots to step over. It's a great warm-up for things to come. Deer Lake is 3.8 miles up this trail.
Emerging from the rocky evergreen forest trail, Deer Lake is a welcome sight. Not the largest of lakes, it's still plenty big for catching some trout or just relaxing, dipping your feet in the water.
Passing Deer Lake, you rise higher and higher. The trees thin out considerably and you pass many snow melt fed ponds commonly referred to as the "potholes". Continuing up and up and up, eventually you reach the Lunch Lake spur trail. Down to the left here is a couple more beautiful alpine lakes, well worth a look.
Shortly after the Lunch Lake junction is Bogachiel Peak. At 5474 feet it is the highest point on this trip. It is at this point you get your first view of Mt. Olympus and the massive Blue Glacier to the south. For the next 2 or so miles, the view to the south continues opening up to reveal more of the glacier. On a clear day, this presents some of the most spectacular photo opportunities. Off to your left, the north, is Seven Lakes basin with a multitude of alpine lakes and more "potholes" to be seen. This is truly the apex of this hike.
As you work your way along the ridge and come over the last rise in the trail, below you opens up Heart Lake. True to its' name, it appears as an upside down heart shaped, glacier fed lake. Not much more than 150 feet across, it is still a wonderful sight. Campgrounds and trails ring the lake and after the long haul up the mountain and over the ridge, its' refreshing waters feel like heaven on your feet.
From here back to the trail head it almost exclusively downhill. The trees begin to encroach upon you once again and shortly you will reach the horse camp on the Sol Duc River. There really isn't much to see here, but it's a welcome sign for those in the know: It's easy going from here.
The remaining 6 or so miles is a leisurely stroll following the Sol Duc through the old growth. After the roller coaster ride you just endured, this final stretch is just what you need to stretch out and cool down before hitting the road and maybe picking up a cold 6 pack of your favorite beverage at the Sol Duc Hot Springs Resort.
This 18 Mile loop isn't for everyone. Only the most die-hard hiker tackles it one day. I normally get it done in 7 to 8 hours, and that's chugging along not really stopping to smell the flowers, of which there are plenty. It is a perfect hike for breaking up into a weekend, staying the night at Lunch or Heart Lake. If you are looking to test yourself, this is the one. Rewarding in every way. The views are second to none and the grades can surely test you, it is most definitely one hike that you MUST do, at least once.