Gachsar is a village in Asara district of Alborz province, en route Karaj-Chalus Road. Its name originates in its nearby gypsum mine, (gach means gypsum in Farsi).
It has a small royal lodge built during the reign of Reza Shah Pahlavi. It was also used as a countryside camp by Qajar kings.
This village has a reputation for having pleasant weather in warm seasons of the year and the snowy winters. The famous tulip garden of Gachsar provides a spectacular tableau of different kinds of tulips that attracts every year thousands of eager tourists to this region.
The dialect of Gachsari Farsi that is spoken by people in this region is mostly similar to Mazandarani, although it is more easily understood in terms of words and conception.
Dizin Ski Resort is only 12km away from the village. Yakhmorad cave and climbing cliff are other attractions near this village.