Mahdishahr is a mountain city in centeral Alburze mountain. East of Tehran with 220 Km distance.
Mahdishahr is a city located in the Semnān Province of Iran on the southern slopes of the Alborz mountains, the administrative centre Mehdishahr County. In the northern part it has a common boundary with Mazandaran Province. Here, the chain of Alborz mountains is very close to the desert of Dasht-e Kavir. Sangesar, specially the northern part of it, is completely mountainous with cold winters, heavy snowfalls but with mild summers.

The area of the county is about 1100 square kilometers. The distance between Sangsar city and Semnan city is 20 kilometers. The altitude is about 1630 meters above sea level.
Mahdi is the Shia Muslim hidden Imam and Shahr means town in Persian, so Mahdishahr literary means town of Mahdi.

The most important network of roads consists of Semnan to Sangsar to Shahmirzad to Fooladmahale axis which connects these places with the city of Sari. This road connects the two provinces of Mazandaran and Semnan.