Spanning 211 miles (339 kilometers), the JMT's breadth is just about as great as Muir's influence. Beginning in the Yosemite Valley and ending at Mount Whitney -- the highest point in the contiguous United States -- the trail winds through three different national parks: Yosemite, Sequoia and Kings Canyon. The JMT runs in concert with a segment of the Pacific Crest Trail, which stretches from Mexico to Canada and traverses the widely varying climates and elevations of California, Oregon and Washington [source: Pacific Crest Trail Association].
As you might guess, the JMT isn't a day hike -- in fact, hikers should be prepared to take some substantial time off work. At an average pace of 10 miles (16 kilometers) per day, hiking the trail's full 211-mile span will probably take you about three weeks [source: Sierra Mountain Center]. Despite its prodigious span, however, the JMT isn't one of the most strenuous trails in the California Sierra -- it's more of an endurance race than a sprint.
Those who trek the full length of the trail reach elevations ranging from 7,560 to 14,494 feet (2.3 to 4.4 kilometers) above sea level [source: Pacific Crest Trail Association]. Most experts recommend that hikers move north to south (from Yosemite Valley to Mount Whitney) in order to slowly allow their bodies to get used to the altitude [source: Bastone]. With only 59 percent of the oxygen that exists at sea level, if you jumped right to the summit of Mount Whitney, you'd probably remember your altitude sickness more than the view [source: Baillie].
As you might imagine with such a long trail, the scenery -- widely considered some of the most beautiful in the United States -- is also highly varied. Hikers will find everything from thick woods to clear rivers and snowy peaks to plunging valleys; visitors during spring and summer might also catch the spectacular wildflowers that the meadows of the JMT are known for.
If you're having trouble convincing your boss to give you three weeks off to go hiking, you're not out of luck. Read on to find out about the various segments of the JMT and the landmarks you'll find along the way.