As late as the 1870s, Half Dome was considered completely unclimbable, but it may now be ascended in several different ways. Thousands of hikers reach the top each year by following a trail from the valley floor. The trail head is only two miles from Half Dome itself, but the circuitous route is 8.5 miles (13.5 kilometers) long. The final ascent is accomplished by following a pair of metal cables raised on posts up the peak's steep but somewhat rounded east face. The cables were constructed in 1919.

Alternatively, over a dozen rock climbing routes lead directly from the valley up Half Dome's vertical north face.

Half Dome is an excellent example of a exfoliation. Half Dome probably never formed a completely round dome. When Half Dome formed, there were fractures in the granite. Water inside the fractures froze and thawed repeatedly. Glaciers eroded the base of the dome. Finally, about 20% of the dome fell and was carried away by the Tenaya glacier, leaving an almost-vertical cliff.

The total 2425 foot distance from the top of the upper falls to the base of the lower falls qualifies Yosemite Falls as the sixth highest waterfall in the world. Although often referred to as a "two-stage drop", the falls actually consist of three sections:

• The 1430 foot plunge qualifies the Upper Falls alone as one of the twenty highest waterfalls in the world. Trails up from the valley floor and down from other regions of the park outside the valley proper lead to both the top and base of upper Yosemite Falls. The upper fall is formed by the swift waters of Yosemite Creek which, after meandering through Eagle Creek Meadow, hurls themselves over the edge of a hanging valley in a spectacular and deafening show of force.

• Between the two obvious main plunges there are a series of cascades and smaller plunges generally referred to as "the cataracts". Taken together these account for another drop of 675 feet, nearly twice the height of the lower falls. Because of the layout of the area, the lack of any major drops in this section and the lack of public access they are all too easy to overlook. Most viewpoints in the valley miss them entirely. The best vantage points for the cataracts are found along the Yosemite Falls trail. Warning: Individuals climbing down from the falls trail towards the cataracts for a better look have required an expensive helicopter rescue due to steep and slippery terrain and features.

• The final 320 foot drop of the Lower Falls, adjacent to an accessible viewing area provides countless park visitors with a close look at this spectacular waterfall. Yosemite Creek emerges from the base of the lower falls and flows into the Merced River nearby. Like many areas of Yosemite the plunge pool at the base of the lower falls is surrounded by dangerous jumbles of talus (in mountaineering and climbing, talus is small broken rock found on mountain slopes and at the base of cliffs) made even more treacherous by the high humidity and resulting slippery surfaces.

In years of little snow, the falls may actually cease flowing altogether in late summer or fall. A very small number of rock climbers have taken the opportunity to climb the normally inaccessible rock face beneath the falls, although this is an extraordinarily dangerous undertaking; a single afternoon thunderstorm could restart the falls, sweeping the climbers off the face.