The Pacific Crest Trail (PCT), officially designated as the Pacific Crest National Scenic Trail, is a long-distance hiking and equestrian trail closely aligned with the highest portion of the Cascade and Sierra Nevada mountain ranges, which lie 100 to 150 miles (160 to 240 km) east of the U.S. Pacific coast. The trail's southern terminus is next to the Mexico–United States border, just south of Campo, California, and its northern terminus is on the Canada–US border, upon which it continues unofficially to the Windy Joe Trail within Manning Park in British Columbia; it passes through the states of California, Oregon, and Washington.

The Pacific Crest Trail is 2,653 mi (4,270 km) long and ranges in elevation from roughly 110 feet (34 m) above sea level near the Bridge of the Gods on the Oregon–Washington border to 13,153 feet (4,009 m) at Forester Pass in the Sierra Nevada. The route passes through 25 national forests and 7 national parks. Its midpoint is near Chester, California (near Mt. Lassen), where the Sierra and Cascade mountain ranges meet. The overall elevation gain for the Pacific Crest Trail is approximately 489,000 ft (149,000 m).

It was designated a National Scenic Trail in 1968, although it was not officially completed until 1993. The PCT was conceived by Clinton Churchill Clarke in 1932. It received official status under the National Trails System Act of 1968.

The Pacific Crest Trail, the Appalachian Trail, and the Continental Divide Trail form what is known as the Triple Crown of Hiking in the United States. The Pacific Crest Trail is also part of the 6,875-mile Great Western Loop.