Karaj (, ) is the fourth largest city in Iran, being in close proximity of the capital Tehran. It is situated in the Central District of Karaj County, Alborz province, Iran, it serves as the capital of the county Although the county hosts a population around 1.97 million, as recorded in the 2016 census, most of the county is rugged mountain. The urban area is the fourth-largest in Iran, after Tehran, Mashhad, and Isfahan. Eshtehard County and Fardis County were split off from Karaj County since the previous census. At the National Census of 2006, Karaj had a population of 1,377,450 in 385,955 households. The latest census in 2016 counted 1,592,492 people in 508,420 households. The earliest records of Karaj date back to the 30th century BC. The city was developed under the rule of the Safavid and Qajar dynasties and is home to historical buildings and memorials from those eras. This city has a unique climate due to access to natural resources such as many trees, rivers, and green plains. After Tehran, Karaj is the largest immigrant-friendly city in Iran, so it has been nicknamed "Little Iran." History The area around Karaj has been inhabited for thousands of years, such as at the Bronze Age site of Tepe Khurvin and the Iron Age site of Kalak. However, the present-day city of Karaj is mostly the result of modern industrial development in the 20th century. Historically, Karaj was mostly significant as a stage on the road between Tehran and Qazvin. In Safavid times, a stone bridge was built that served as the main crossing into the town. The large Shah-Abbasi Caravansary, located at the southeast of Towhid Square, was built in the same era, under the rule of Šāh Esmāil. In 1810, the Qajar prince Soleyman Mirza built the Soleymaniyeh Palace at Kajar to serve as a summer resort. The palace had four towers and was surrounded by gardens, and its reception room featured a pair of paintings by Abdallah Khan Naqqashbandi. By 1860, however, the palace was described as abandoned and only used as a shelter for travelers. Naser al-Din Shah Qajar later renovated the palace. In 1917, a School of Farming was established on the site, replacing the earlier Mozaffari Agricultural School in Tehran. Later, Reza Shah Pahlavi granted it to the University of Tehran's new Faculty of Agriculture. In the 1930s, plans were drawn up for a