The Rachel Carson Trail is a 35.7-mile (57.5 km) hikingtrail in Allegheny County, Pennsylvania in the United States. The trail stretches along a meandering path from Harrison Hills Park to North Park, crossing through a variety of dense woodlands, open meadows, streams, steep bluffs, power line clearings, as well as skirting the boundaries of local farms and suburban areas. There are no camps or shelters along the way, meaning the trail is intended for day-hiking. The trail contains hazardous terrain and is steep, rising 8,151 feet and dropping 8,214 feet. Few bridges have been built, causing hikers to cross waterways.
Every year since 1996, the Rachel Carson Trails Conservancy hosts a "Rachel Carson Trail Challenge". Participants attempt a 34-mile long, one-day, sunrise to sunset endurance hike along the trail. The stated challenge is simply to finish the entire stretch before sunset, or approximately 15 hours. Two shorter challenge routes of 18 miles and 8 miles are offered, as well. The trail has also been part of the 100 Mile Quest, a challenge to hike 100 miles in one year.