- Strontian, Highland, Scotland, United Kingdom1
- Succasunna, Morris County, New Jersey, United States1
- Sulphur City, Calcasieu Parish, Louisiana, United States1
- Sussex County, New Jersey, United States2
- Sweden3
- Texas, Lancaster County, Pennsylvania, United States3
- Thuringia, Germany3
- Topsham, Sagadahoc County, Maine, United States2
- Towns County, Georgia, United States1
- Transylvania, Romania1
- Trenton, Mercer County, New Jersey, United States1
- Trumbull, Fairfield County, Connecticut, United States1
- Trumbull, Fairfield County,Connecticut, United States1
- Tunaberg, Nyk'ping, S'dermanland, Sweden1
- Tuscany, Italy1
- Tyre, Liban-Sud, Lebanon1
- Unity, Sullivan County, New Hampshire, United States1
- Upper Dublin Township, Montgomery County, Pennsylvania, United States1
- Ut' Mines, Ut', S'dermanland, Sweden1
- Utö Mines, Utö, Södermanland, Sweden2