Katale khor (Persian: کتلهخور,Azerbaijani: کتله خور) is a cave located in Zanjan Province, Iran. It is situated at 120 km south of Zanjan city and 410 km away from Tehran. The name, Katale khor, means "mount of Sun". Geological studies in 1984 showed that the cave formation dates back to the Jurassic period. It is believed that the cave joins to Ali Sadr Cave in Hamadan province. The road from Zanjan to Khatalekhor cave passes Soltaniyeh, the biggest brick dome of the world.
This cave was discovered about 90 years ago but it was registered by Ahmad Jamali.
Coordinates: 35°50′08″N 48°09′42″E / 35.83556°N 48.16167°E