Follow the Wonderland Trail from the Box Canyon area to the top of the Cowlitz Divide. Then look for the Old Cowlitz Divide Trail heading south. Follow this trail for about a mile to the lake. Says Anonymous
Saint Jacobs Lake is wonderful enough to spend more than a day at, Mt Rainier National Park - Ohanapecosh Camp Ground is a wonderful local campground. The beauty of mother nature reveals herself at Cougar Falls, and good skiing awaits you at White
Pass. A visit to Saint Jacobs Lake wouldn't be complete without taking a look at Saint Johns Falls. Hiking along the Backbone Ridge Trail is good fun, and while you're here, you could go to Twin Falls Creek.