The trail extends 428 miles (689 km) from Cascade Locks on the Columbia River south to Siskiyou Summit near the Oregon-California border.

[1][2][3] The Oregon Skyline Trail was established in 1920 when a United States Forest Service team led by ranger Fredrick William Cleator explored and marked a 260-mile (420 km) route between Mount Hood and Crater Lake.

[7][8] By 1936 the Oregon Skyline Trail had been extended to reach across the state, from the Columbia Gorge Ranger Station near the town of Cascade Locks south to beyond Soda Mountain, just a few miles from the California border.

The trail was then about 400 miles (640 km) long and had been extensively relocated to more closely follow the backbone of the mountains, thereby affording hikers and equestrians more scenic views.

The trail then courses south at or near the crest of the Cascade Mountains, passing prominent volcanoes and natural features.

Near Pilot Rock, the trail comes to within two miles of the California border before extending further west to its southern terminus at Siskiyou Summit.

[13][10] However, by 1945 the trail had been oriented in a more southerly direction, primarily along unpaved roads and through private property, to Copco Lake in northern California.