Distance: 2.4 miles (3.8 km) round trip (the red line only)
Elevation at trailhead: 4,000 feet (1,220 meters)
Elevation Gain: 100 feet (30 meters)
Map Notes: The red line marks the trail ending at Mirror Lake. If you plan to continue past Mirror Lake and hike the entire Tenaya Canyon loop (assuming the full trail ever reopens), the yellow line shows the rest of your route. You'll find a dramatic transition from Mirror Lake to the trail beyond it, crowdwise - not unlike the difference between 4:55 and 5:01 on Friday at offices all over the world. At least in the summer, anyway; crowds are much thinner throughout the trail in the wintertime.
This map places the trailhead at the bus stop nearest Mirror Lake, but you can start from just about anywhere in the eastern valley and walk to the trailhead without regretting the time you passed along the way. There are big blue letter P's at the three closest large parking lots: from left to right, Yosemite Village, Curry Village, and the Trailhead Parking Lot. You can catch one of the free shuttle buses at the first two lots and ride all the way to the trailhead. Be warned that the shuttle buses are not for the claustrophobic on summer weekends. Then again, neither is Mirror Lake.