From NPS:

The Sequoia and Kings Canyon Wilderness encompasses hundreds of thousands of acres of pristine High Sierra country and is the crown jewel of the parks.

Over 723,000 acres, some 84% of Sequoia and Kings Canyon National Parks, was designated as Wilderness as part of the 1984 California Wilderness Act. And an additional 110,000 acres of these parks are managed as wilderness per National Park Service policies.

Getting permits

Day hikers do not need a permit but overnight hikers do.

Permits are issued based on the location of the trailhead where you begin your trip. For example, if you plan to enter Dusy Basin in Kings Canyon National Park through Bishop Pass by starting from South Lake, you would get your permit from the Inyo National Forest White Mountain Ranger District Office since the South Lake trailhead is in the Inyo National Forest. However, hikers wishing to enter Sequoia and Kings Canyon National Parks from the Big Meadows Road trailheads in Giant Sequoia National Monument should get their permits from Grant Grove.