Alta Peak (3415m) is in Sequoia National Park.
The most commonly used trailhead is the Wolverton trailhead, not far from Lodgepole's visitor center (south on 198 toward Visalia)
at about 2300 meters of elevation.
After 3 kms take the right trail (the left one goes to Pear Lake). The trails climbs very gently to Panther Gap (2500m) where one starts seeing the Great Western Divide. After the fork for Alta Meadows, the trail continues east and gets a bit steeper. You are almost never above the tree line.
The view of the western Sierra from the summit is famous, although one can argue that it is famous mainly among people who haven't seen higher views. Anyway, you do see Milestone Peak and, if you know where to look, Mt Whitney.