No trip to Yosemite is complete without a drive up to Glacier Point. Glacier Point, an overlook with a commanding view of Yosemite Valley, Half Dome, and the High Sierra is located 30 miles (one hour) from Yosemite Valley. The road ends at Glacier Point and it is a short walk to the viewpoint.
If you go:
Be sure to check road conditions, the road is closed from sometime in November through early May or late June. From mid-December through March the road is plowed only as far as the Badger Pass ski area and Glacier Point can be reached via skis or snowshoes only.
Links:

Glacier Point Road
Yosemite National Park, California 95389 USA
Mailing address:
P.O. Box 577
Yosemite, CA 95389 USA
Phone Numbers:
Park Information
+1 (209) 372-0200
+1 (209) 372-0200
Message from RoadTrip America