The history of Karaj dates back many centuries. The stone built Zoroastrian fire temple of Takht-e-Rostam from the Parthian era is a testament to this.
The Soleimanieh palace (currently housing a college of Agriculture), the mausoleum of Shahzadeh Soleiman, Imamzadeh Rahman and Zeid Palang Abad-e-Eshtehard are other historical relics of the Karaj area.
During the Pahlavi dynasty era, the Morvarid Palace was constructed in nearby Mehrshahr district, designed by the Frank Lloyd Wright Foundation.
Especially after the Islamic Revolution thousands of people started to migrate to this pleasant small town making it one of the biggest cities of Iran in less then 3 decades. Currently Karaj is the center of Alborz province located at west of Tehran. Alborz province itself is the youngest and smallest province of Iran. It is named after Alborz mountain range, which is located at the north of Iran. It also provides a great share of water supply of Tehran because of its rich resources such as rivers and springs.
It is connected by freeway, railway to Tehran 40 km east and Qazvin 100 km northwest, and by commuter rail to Tehran subway system (Metro).
Karaj's climate is a bit cooler than Tehran and it receives 260 mm of rain annually. The economical base for Karaj is its proximity to Tehran, where transportation of products between the capital and the Caspian Sea is central. Chemicals, fertilizers and processed agricultural goods are also produced here. It possess importance in agriculture and industry. Many of the most important factories of Iran are located near it.
Karaj is a multicultural city, due to migrants from all around Iran, that is why Karaj is called as Little Iran
Soleimanyeh Palace with five storey tower (Gajar Era).