Yosemite National Park

Yosemite National Park embraces a spectacular tract of mountain-and-valley scenery in the Sierra Nevada, which was set aside as a national park in 1890. The park harbors a grand collection of waterfalls, meadows, and forests that include groves of giant sequoias, the world's largest living things. Highlights of the park include Yosemite Valley, and its high cliffs and waterfalls; Wawona's history center and historic hotel; the Mariposa Grove, which contains hundreds of ancient giant sequoias; Glacier Point's (summer-fall) spectacular view of Yosemite Valley and the high country; Tuolumne Meadows (summer-fall), a large subalpine meadow surrounded by mountain peaks; and Hetch Hetchy, a reservoir in a valley considered a twin of Yosemite Valley.
There is so much to do in Yosemite, and it offers opportunities for people of all ages and backgrounds. If you're planning a trip to Yosemite, first decide during which season you plan to visit, then decide where you'll spend the night (if you spend the night) so you can make lodging or camping reservations. Then, you can find the answer to the age-old question about what there is to do in Yosemite.
Map
Seasonality / Weather
Yosemite National Park is open 24 hours per day, 365 days per year, and no reservations are required to visit. However, the Hetch Hetchy Entrance Station is open only during daylight hours (approximately) and some roads are closed due to snow from around November through May or June.
Directions
From San Francisco/Bay area take I-580 east to I-205 east to Highway 120 east (Manteca) or Highway 140 east (Merced) into Yosemite National Park.
From Sacramento take Highway 99 south to Highway 120 east (Manteca) or Highway 140 east (Merced) into Yosemite National Park.
From Reno & Lake Tahoe, approximately June through October, conditions permitting, Take US 395 south to Lee Vining; take Highway 120 west into Yosemite National Park (open late May/June through October, depending on conditions). Year round take I-80 or I-50 west to Sacramento; take Highway 99 south to Highway 120 east (Manteca) or Highway 140 east (Merced) into Yosemite National Park.
From the Los Angeles area Take I-5 north (or I-405 north to I-5) to Highway 99 north to Highway 41 north (Fresno) into Yosemite National Park.
From Las Vegas June through October, conditions permitting, take I-15 south to Barstow; Highway 58 west to the junction with US 395; go north on US 395 to near Lee Vining; take Highway 120 west into Yosemite National Park (open late May/early June through October, depending on conditions).
From November through May take I-15 south to Barstow; Highway 58 west to Bakersfield; take Highway 99 north to Fresno. In Fresno, take Highway 41 north into Yosemite National Park
Bus service is available to Yosemite Valley from cities throughout California (and the rest of the United States). Amtrak provides a combination of train and bus service to Yosemite Valley. Greyhound provides bus service to Merced, where you can transfer to YARTS to continue to Yosemite Valley. Yosemite Area Regional Transportation System (YARTS) buses also provide service from communities along Highway 140 between Merced and Yosemite (including Mariposa, Midpines, and El Portal). During summer, service is also available from east of Yosemite, via Highway 120 (including Lee Vining, June Lake, and Mammoth Lakes). Free shuttle service is available within some (but not all) areas of the park.
If you arrive in Yosemite Valley by bus, access to other areas of the park is possible, include Yosemite Valley (free shuttle service around eastern Yosemite Valley), Glacier Point (late May/June through October via fee-based tour), Badger Pass (mid December through March via free shuttle), Wawona (summer only; very limited shuttle service available from Wawona to Yosemite Valley in the morning and from Yosemite Valley to Wawona in the afternoon), Tioga Road/Tuolumne Meadows (July and August, along with weekends in June and September, via fee-based tour and YARTS Highway 120 East bus), Tuolumne Meadows (summer only; free shuttle service in the Tuolumne Meadows area). Hetch Hetchy Valley and Hodgdon Meadow have no public transportation.