- Laurens County (S.C.)2
- Leadhills, South Lanarkshire, Scotland, United Kingdom1
- Lewes, East Sussex, England, United Kingdom1
- Lewes, Sussex, England, United Kingdom1
- Lockport, Niagara County, New York, United States1
- Lubietova, Banskobystricky, Slovakia1
- Magnet Cove, Hot Spring County, Arkansas, United States1
- Marlboro County (S.C.)1
- Massachusetts, United States2
- Matlock, Derbyshire, England, United Kingdom1
- Middletown, Middlesex County, Connecticut, United States1
- Midlands1
- Milos, Nisos, Cyclade Islands, Aegean Islands, Greece1
- Mississippi1
- Mount Vesuvius, Napoli province, Campania, Italy1
- Neidermennig, Rheinland, Germany1
- North Carolina1
- North Stafford, Connecticut, United States1
- Norwich, Hampshire County, Massachusetts, United States1
- Norwich, New London County, Connecticut, United States1