- ChemGlobe: Thorium - Electronic, thermal, and steric data along with an isotope table.
- ChemicalElements.com: Thorium - Basic information, atomic structure, and isotopes.
- EnvironmentalChemistry.com: Thorium - Atomic structure, chemical and physical properties, and table of nuclides.
- It's Elemental: Thorium - Basic physical and historical information.
- LANL: Thorium - Uses, properties, production, properties.
- Lenntech: Thorium - Physical data, chemical properties, health and environmental effects.
- Thorium - Information about uses, what is thorium, sources, coutries reserves of thorium.
- Thorium - An information source of thorium and thorium-related topics.
- USGS Minerals Information: Thorium - Statistics and information on the worldwide supply, demand, and flow of the element (PDF format).
- Visual Elements: Thorium - Image, general and physical information, and key isotopes.
- WebElements: Thorium - Extensive information on history, uses, occurrence, compounds, and properties.
- Wikipedia: Thorium - Properties of the element, including its history, applications, and characteristics.
