S
- Swiss Transalp: Haute-Nendaz to Mauvoisin
- Swiss Transalp: Intertkirchen to Grindelwald
- Swiss Transalp: Lauenen to Haute-Nendaz
- Swiss Transalp: Leissigen to Adelboden
- Swiss Transalp: Lucerne to Intertkirchen
- Swiss Transalp: Mauvoisin to Aosta
- Switcheroo
- Switchgrass Trail System
- Switzer Falls
- Swope Park Loop
- Sycamore Cove
- Sycamore Cove Loop
- Sydenham Hill Wood to Dulwich Village
- Syllamo: Bad Branch Trail
- Syllamo: Bald Scrappy Trail
- Syllamo: Jack's Branch Trail
- Syllamo: Scrappy Mountain Trail
- Syllamo: White River Bluff Trail
- Syncline Trails: Big Loop
- Syncline Trails: Big Loop
- Syncline Trails: Hidden Canyon Loop
- Syncline Trails: Little Maui to Little Moab Loop
- Syncline Trails: Little Moab Loop