Trending in a north–south direction from the Oregon border down to near the town of Weitchpec and 20 miles (32 km) inland from the Pacific Ocean, the Siskiyous are dotted by rocky peaks rising over 6,000 feet (1,800 m) from the surrounding lowlands.

[3] It is notable for the vast amounts of old-growth forests and many endemic species of wildflowers, shrubs and trees, as well as one of the world's largest concentrations of lilies.

[4] The wilderness is home to several rare species, including wolverine, marten, fisher, northern spotted owl and Roosevelt elk.

In the southern part of the wilderness, the Kelsey National Recreation Trail begins at Bear Lake, and the experienced hiker can walk for about 20 miles (32 km) to the Smith River.

[6] The Bigfoot Trail traverses the crest of the wilderness from north to south, through some of the most remote areas.