Tehran Province is located to the north of the central plateau of Iran. Tehran Province borders Māzandarān Province in the north, Qom Province in the south, Semnān Province in the east, and Alborz Province in the west. The metropolis of Tehran is the capital city of the province and of Iran. Tehran, with a population of more than 7 million, is ranked amongst the 20 most populous metropolitan cities of the world.

The largest rivers of this province are Karaj River and Jajrud River. Mountain ranges such as The Alborz span the north; Savad Kooh and Firooz Kooh are located in the north east; Lavasanat, Qarah Daq, Shemiranat, Hassan Abad and Namak Mountains are in the southern areas; Bibi Shahr Banoo and Alqadr are situated in the south east and the heights of Qasr-e-Firoozeh being located to the east of the province.

Environmentally, the climate of Tehran province in the southern areas is warm and dry, but in the mountain vicinity is cold and semi-humid, and in the higher regions is cold with long winters. Tehran city has moderate winters and hot summers. On the whole, the province has a semi arid, steppe climate in the south and an alpine climate in the north.